Potash alum formula D. We will look into the preparation of Potash Alum in detail in this article. The aluminium, potassium and sulphate ions are present in the ratio 1:1:2 in potash alum. 24 H 2 O. The chemical formula for potash alum is KAl(SO4)2. The chemical formula for Potash alum can be given as K 2 SO 4. Gostaríamos de exibir a descriçãoaqui, mas o site que você está não nos permite. It is commonly encountered as the Q9: What is Potash Alum? Answer: Potash alum, also known as potassium aluminium sulphate, is a chemical compound most commonly found in the dodecahydrate form. In the above formula, X can be a metal such as potassium (K), sodium (Na Potash Alum with Formula Potash alum, also known as potassium alum, is a naturally occurring mineral salt that has been used for centuries for its various purposes. KAl(SO 4) 2. Instant Answer. Potash alum generally came as the dodecahydrate, KAl(SO 4) 2. Uses of Potash alum. Its chemical formula is KAl(SO 4) 2 and it is commonly found in its dodecahydrate form as KAl(SO 4) 2 ·12(H 2 O). only one type of ion. Is alum a mineral? Ans. org Location Data. Ans: Hint: Formality of a solution is defined as the number of formula weights of solute per liter of solution. This is the type of alum that you find in the grocery store for pickling. It is made by the process of solidifying alum from conc—arrangement containing equimolar measures of aluminium sulphate and potassium sulphate. Potash alum has a molar mass of 258. Find out the chemical formula, structure, uses and yield calculation of Potash alum, also known as potassium aluminum sulfate, is a chemical compound with the formula KAl(SO₄)₂·12H₂O. Alums can easily be produced by precipitation from an Learn how to prepare potash alum, a double metal sulphate of potassium and aluminium, in a laboratory setting. Chemical formula KAl (SO 4) 2. Potash alum is a double salt, its aqueous solution shows the characteristics of: asked Apr 16, 2022 in Chemistry by Sujalvasani (121k points) class-12; d-block-elements; 0 votes. 78g } potash alum is dissolved in a { 2L } solution. The general formula of alums family is M 1+ M 3+ (XO 4) 2 ·12H 2 O where M 1+ is a monovalent cation (NH 4, K, Rb, Cs, Na) and M 3+ is a trivalent cation (Al, Ga, In, Cr, Fe), X = S, Se. Al 2 (SO 4) 3. two type of ions. The surge continued into 2022, driven by geopolitical tensions and the Russian invasion of Ukraine, peaking at US$1,202 per tonne in April. Both of them are crucial examples of inorganic compounds. It is used in various fields like medicine, ceramic industries, baking industries etc. Al2(SO4)3. Potash alum's chemical formula is. We will discuss them briefly below. An aqueous solution of potash alum give. It is a Potash, various potassium compounds, chiefly crude potassium carbonate. asked Nov 21, 2019 in Chemistry by Ranjeet01 (58. The Crystal of potassium alum, KAl(SO 4) 2 ·12H 2 O. A. 4k points) bseb model set; Features. Thus, the number of atoms present in 1 mole of potash alum will be 32 N. Alum exists in different forms: potash alum, soda alum, ammonium alum, and chrome alum. Step 1/2 Potash alum is also known as potassium alum. KAl(SO₄)₂·12H₂O. Here, the octahedral coordination of the metal ions depends on the crystal structure, unlike coordination compounds that maintain the same coordination geometry in the solid and solution states. In fertilizer terminology, potassium formula of potash alum. There are 3 OEM, 1 ODM, 2 Self Brand. Potash alum, also known as potassium aluminum sulfate, is an inorganic compound with the chemical formula KAl(SO₄)₂·12H₂O. Al 2 (SO 4) 3 . A crystal of some salt that contains water of crystallization is called a Hydrated substance. It is aluminum potassium sulfate. 1. It is a double salt used in medicine, water treatment, dyeing, and other applications. 24H2O, also known as potassium alum or aluminium potassium sulfate. Alum is generally available in its crystalline form or most often as a powder. It normally occurs in the form of the dodecahydrate, meaning that each molecule of the compound is associated with twelve molecules of water Potash alum and Mohr’s Salt. Potash Alum is a A. Potash alum dodecahydrate; Potassium aluminum disulfate dodecahydrate; Alum, potassium [USP] Occurs naturally as efflorescence on alum shale and as feather alum on lava; Used to dress fur skins Empirical Formula: KAl(SO 4) 2 •12(H 2 O) Environment: Derived from the oxidation of sulfide minerals and potassium-bearing Link to MinDat. 4, Potash prices declined from 2013 to 2016 and remained relatively low until 2020. [13] [14] Does not contain potassium oxide (K 2 O), which plants do not take up; [15] the amount of Potassium alum, commonly known as potash alum, is a chemical compound with the formula KAl(SO4)2·12H2O. An alum (/ ˈ æ l ə m /) is a type of chemical compound, usually a hydrated double sulfate salt of aluminium with the general formula X Al(SO 4) 2 ·12 H 2 O, such that X is a monovalent It begins with introducing the uses of alum and its chemical formula. Potassium aluminum sulfate, also known as potassium alum or potash alum, has a molecular formula of K 2 (SO 4)·Al 2 (SO 4) 3 ·24H 2 O or KAl(SO 4) 2 ·12H 2 O. The names caustic potash, potassa, and lye are frequently used for potassium hydroxide (see potassium). Its chemical name is Potassium Aluminium Sulphate. The chemical formula for Potash Alum is KAl(SO 4) 2 ·12H 2 O. In alum aluminum sulfate, also known as potassium alum or potash alum, has a molecular formula of K 2 (SO 4)·Al 2 (SO 4) 3 ·24H 2 O or KAl(SO 4) 2 ·12H 2 O. Double salt B. It is usually produced in its hydrate form, which has 12 molecules of water attached to it. 192 g/mol (anhydrous) and 474. This crystallises in neutral solution as an octahedral structure and as a cubic structure in alkali solution, with a space group of Pa -3 and a lattice parameter of 12. Potassium alum, also known as potassium aluminum sulfate or aluminum potassium sulfate, with chemical formula KAI(SO4)2 and usually present in the dodecahydrate form Potash alum has the chemical formula KAl(SO 4) 2. 1 Study App and Learning App with Instant Video Solutions for NCERT Class 6, Class 7, Class 8, Class 9, Class 10, Class 11 and Class 12, IIT JEE prep, NEET preparation and CBSE, UP Board, Bihar Board, Rajasthan Board, MP Board, Telangana Board etc Kalinite is a mineral with formula of KAl(S 6+ O 4) 2 ·11H 2 O or KAl(SO 4) 2 ·11H 2 O. Here, N is the Avogadro number. The document describes the preparation of potash alum from scrap aluminum. . Aluminium sulphate contains 18 number of water molecules (Al (SO 4) 3,18H 2 O). Practical Based Questions. Its mineral form is known Also Read: Hing: Uses, Benefits, Side Effects & More! Potential Uses of Alum 1. It is a colorless, crystalline solid that tastes sour. The student aims to prepare potash alum from scrap aluminum under the guidance of their Common name Chemical name (Formula) Potash fertilizer: Up to the early 20th century:potassium carbonate (K 2 CO 3). 38 (dodecahydrate) 258. Alum is the common name for this chemical compound, given the nomenclature of potassium aluminum sulfate dodecahydrate. (Image will be uploaded soon) The molar mass of the Potash Alum is 258. Potash alum is water-soluble and slightly acidic as it causes litmus paper to turn red. Click here:point_up_2:to get an answer to your question :writing_hand:07what is the chemical formula of potash aluma k a llefts o4right2 cdot 12 h2 Escherichia Genomics glade to invite your expression of interest to conduct DNA Workshop in association of Escherichia Genomics and your most prestigious ins. Name Origin: Named for the element K and the Latin, alumen. Formula. Use app Login. 37 g/mol (dodecahydrate). 24H 2 O, is obtained by crystallizing a concentrated solution of potassium sulfate and aluminium sulfate in equal molar amounts. Potash alum is widely used as the potassium sulphate dodecahydrate. Name Potassium sulphate Aluminium sulphate Potashalum . 192 g/mol. It is prepared by crystallizing the alum from a concentrated solution containing equimolar amounts of potassium sulfate and aluminium sulfate. Potassium alum is the hydrated form of aluminum potassium sulfate. The chemical formula for Potash alum can be given as. #chemistry #k2chemistry #atoms #chemicalformula #education #chemistryknowledge #compound #molecules #k2chemistryclass #intermolecularforces #bonding #intram Potash-alum definition: Alum , hydrated potassium aluminium sulphate , formula K 2 SO 4 . Find out how to prepare it, its properties, uses and examples in water treatment, tanning, fire retardant and more. It is commonly used in water purification, leather tanning, fireproof textiles, and baking powder. Formula K2 S 04 Al~(S04)~. It also has cosmetic uses as a deodorant and as an aftershave treatment. Source for information on Aluminum Potassium Sulfate potash alum, potassium alum, and kalinite. Potassium alum or potash alum is used most, although ammonium alum, ferric alum, and soda alum may be used for many similar purposes. The commonly encountered type of alum is known as potash alum or potassium alum. Potash Alum is a chemical compound, the dual sulfate of aluminium and potassium. It used in antiperspirant deodorant, shaving products, acne care products, etc. 12H 2 O and the chemical name potassium aluminium sulphate. Chemical Properties. Find high quality Potash Alum Formula Suppliers on Alibaba. It is commonly encountered as the dodecahydrate, KAl(SO4)2·12H2O. Since, alum represents a class of compounds, its general chemical formula is given as follows: The chemical Formula of Alum is XAl(SO 4) 2. Used in printing, fabrics, dyeing, manufacturing of paper, vegetable glue, baking powder, purifying water, clarifying sugar, as Click here:point_up_2:to get an answer to your question :writing_hand:an aqueous solution of potash alum give. Soda Alum: Soda alum has the formula NaAl(S O 4) 2 ·12H 2 O. 24H 2 O is the chemical formula for potash Answer: Diluted sulfuric acid is used to prepare potash alum to inhibit the hydrolysis of aluminium sulphate. The following formula was used to calculate the alum content (%): The formula for this compound is KAl[SO 4] 2. Potassium alum, potash alum, or potassium aluminium sulfate is a chemical compound: the double sulfate of potassium and aluminium, with chemical formula KAl(SO 4) 2. ∴ 1 mole of potash alum contains N molecules. m. Alum can be found in many forms, such as potash alum, soda alum, ammonium alum, and chrome alum. Potash alum or fitkari is used to clean the water as the potassium sulfate On heating potash alum, it losses water of crystallisation. 24H2O) from aluminum scrap through a series of chemical reactions. It’s a two-salt compound that’s commonly utilised in medicine and water purification. 1 answer. Potassium alum or potash alum is the potassium double sulfate of aluminium. Alum Formula. It helps in dissolving aluminium sulphate in warm water. It is commonly encountered as the dodecahydrate, KAl(SO4)2·12H2O. In this form, it occurs as white odorless crystals. It is a double salt that is used commonly in the field of medicine and the water treatment process. 12H 2 O, where A and B are monovalent and trivalent cations. Naturally occuring mineral potash alum is known as alum - (K). General formula ---- X = Monovalent cation ; M = Trivalent cation Some important alum and their names are given below: Potash alum is used in papermaking, in fire extinguishers, in food stuffs and in purification of water soda alum used in baking powders and chrome alum is used in tanning leather and water proofing fabrics. A. Potassium alum, potash alum, or potassium aluminium sulphate is just a chemical compound with the formula KAl(SO 4) 2. The common name of Potash Alum is fitkari. Potash alum, often known as potassium alum, is the most common alum. What is the potassium, aluminium and sulphate ratio in the potash alum? Answer: The chemical formula of potash alum is K 2 SO 4. It's a double sulfate mineral that includes both potassium and aluminum. 24 H 2 O . 18. K2S04. Potassium aluminum sulfate dodecahydrate (potash alum), which has the chemical formula KAl(SO 4) 2 ·12H 2 O, belongs to a large family of isotopic compounds called alums. S. number 7784-24-9 (dodecahydrate) 10043-67-1 (anhydrous) Chemical formula AlK(SO 4) 2 · xH 2O (x = 0 or 12) Formula weight 474. Suggest specific experiments to specify whether it is a complex or double salt. KAlO Alibaba offers 8 Potash Alum Formula Suppliers, and Potash Alum Formula Manufacturers, Distributors, Factories, Companies. Hypothesis as the potash alum study material: The chemical formula of potash alum is K 2 SO 4. Alum potash is a simple salt. Find out how to prepare, dissociate, react and use potash alum in various applications. 1 Production of potash alum from aluminium dross As described in the introduction chapter, These are hydrated double sulphate salts with an empirical formula of AB(SO 4) 2. Crystals of it are transparent, and it is white when made into a powder. Solubility: It is soluble in water, with solubility increasing with temperature. It is a hydrated double salt that consists of aluminum, potassium, sulfur, and oxygen. The crystal of potash alum is octahedral in shape. Potential Use of Alum for Infections. Beginning from the late 19th century: one or more of potassium chloride (KCl), potassium sulfate (K 2 SO 4) or potassium nitrate (KNO 3). It is important to note that this compound is a salt, and so it fully dissolves into individual ions in solution. 12H₂O. The chemical compound potassium alum refers to potash alum or tawas. 1 Structures. Al(SO 4) 3. The IMA symbol is Kli. 12H 2 O . Find out how to prepare it, its properties, Learn how to prepare potash alum, a double salt with the formula K2SO4. Potash alum is also known as Potassium alum or Potassium aluminium sulfate. Potash alum has the chemical formula - K 2 (SO 4)·Al 2 (SO 4) 3 ·24H 2 O. Amongst its fundamental properties you will find: Natural antiseptic It is an inorganic compound with an empirical formula of AB(SO 4) 2 ·12H 2 O. Other potassium aluminium sulfate minerals are alunite and kalinite. B. Potash Alum. Potash alum is commonly referred to as "alum" in various contexts, though several other chemical compounds are also known as alums. A l 2 ( S O 4 ) 3 . 12 H 2 O: Its chemical name is Hydrated Potassium aluminum sulfate. Potassium aluminate can be used to produce potassium alum with sulfuric acid in this reaction. Potash alum is used in purification of water. Because it is a Hydrated substance. Potassium aluminium sulfate, or potash alum, or potassium alum, is a chemical compound. 12H2O. Potassium aluminium sulfate is otherwise known as potash alum or potassium alum. Its chemical formula is KAl(SO4)2·12H2O, which represents its composition of potassium (K), aluminum (Al), sulfur (S), and oxygen (O) atoms, along with twelve water molecules. 24H2O, from potassium sulfate and aluminium sulfate. The common Alum is Potash Alum or Potassium Alum. It provides the aim, requirements, theory, reactions, procedure, observations and result. It is commonly used in the purification of water. The formula of potash alum is KAl(S0 4) 2, also known as potassium alum. On cooling the alum crystallizes which are collected by filtration and then dried at room temperature. Video Answer. Its chemical formula is KAl(SO 4) 2 and it is commonly found in its dodecahydrate form as KAl(SO 4) 2 ·12(H 2 O). Potassium Alum: Potassium alum is also known as potash alum or tawas. Yes. It is commonly encountered as the dodecahydrate, Learn about potash alum, a chemical compound of potassium, aluminum and sulfate, with the formula K2SO4. One molecule of potash alum contains 32 atoms. A12(S04)3. Production | Uses | Safety | Side effects . Properties The empirical formula of potash alum, KAl (SO 4) 2. When heated they liquefy and if the heating is continued, the water of crystallization is driven off. Simple Compound. three type of ions. Al 2 (SO 4 ) 3 . Potassium alum, potash alum, or potassium aluminium sulfate is a chemical compound: the double sulfate of potassium and aluminium, with chemical formula KAl(SO4)2. The chemical structure of potash alum is as follow: (Image will be uploaded soon) The formula of the hydrate is KAl(SO4)2·12H2O. It The chemical formula for potash alum is KAl(SO₄)₂·12H₂O, and it is commonly referred to as potassium aluminum sulfate in chemical nomenclature. You visited us 0 times! Enjoying our articles? Unlock Full Access! Question. Potassium alum is a double salt that is extensively utilised in the production of medicine and the treatment of water. Click here👆to get an answer to your question ️ What is the chemical formula of Potash alum? Potash alum 5. Alum is a hydrous potassium aluminium sulphate mineral. Structure Chemical formula. See more Potassium alum, potash alum, or potassium aluminium sulfate is a chemical compound first mentioned under various Sanskrit names in Ayurvedic medicinal texts such as charak samhita, sushrut samhita, and ashtang hridaya; is chemically defined as the double sulfate of potassium and aluminium, with chemical formula KAl(SO4)2. Figure 1 − Structure of Potash Alum. It is a type of alum commonly used in various applications due to Learn about this topic in these articles: production. Calculate the formality of solution when { 4. 24 H 2 O; The chemical name of potash alum is P otassium aluminum sulfate. Q8. 12H_{2}O}$. Potash alum is soluble in water and it turns litmus paper red. A l 2 (S O 4) 3. The density of Potash Kalinite; Potash alum; Potassium alum dodecahydrate; Alum; white alum; Aluminiumkaliumbis(sulfat Alums have the general formula M 2 SO 4 ·M III 2 (SO 4) 3 ·24H 2 O, where M is one of alkali metals (potassium, sodium, Iron Alum: Chemical Formula: KFe(SO 4) 2 ·12H 2 O; Contains iron instead of aluminum; used in water purification and as a mordant in dyeing. Guides. Soda Alum: Soda alum has the formula Potash alum. Potash alum, also known scientifically as potassium aluminum sulfate, is a chemical compound with the formula KAl(SO₄)₂·12H₂O. Solve. The molar mass of Potash alum can be defined as a chemical compound in science. K 2 SO 4. 9. Answer Its chemical formula is KAl(SO4)2. Solved by verified expert Solved on Dec. The chemical formula of potash alum is K 2 SO 4. Read More The chemical formula of potash alum is KAl(SO 4) 2, but it is also written as AlK(SO 4) 2. Lo bhaya samajh loPotassium alum, potash alum, or potassium aluminum sulfate is a chemical compound: the potassium double sulfate of aluminium. Author links open overlay panel Moath Refat a b c, in the calibration regression equation to determine the alum amount in (g). Its chemical formula is KAl(SO 4) 2. (~l") and sulphate ions (SO:-) Jhe names and gram formula weights of main compounds involved in this experiment are listed below. The chemical formula for the same is K 2 SO 4. Some of the uses of alums are given below: Alums are widely used in water treatment plants and in the purification of drinking water as a chemical flocculant. Its mineral form is known Potash alum: Potash alum is a chemical compound widely used as Potassium sulphate dodecahydrate. Thanks Potash Alum - It is also known as Potassium Alum. 24H2O. This is most commonly found as the dodecahydrate KAl(SO 4) 2 ·12H 2 O. The required The chemical formula of Potash Alum is written as $\mathrm{KAI(SO_{4})_{2}. Its chemical formula is KAl(SO4)2 and it is commonly found in its dodecahydrate form as KAl(SO4)2 12H2O. Potash Alum – Alum in its single form is also commonly known as potassium alum or potash alum. Learn about potash alum, a double salt of potassium sulfate and aluminium sulfate, with the formula K 2 SO 4 . Synonym: Native Alum : Potash Alum : Potassium-alum - Renamed to Alum-(K) by Mineralogical Record, v39 (2008), p131 regular octahedron crystals with flattened corners. Reactions. 24H20 (sometimes written AlK(S04)2·12H20) is white, odorless crystals having an astringent taste, and is soluble in water, insoluble in alcohol, and noncombustible. Potash alum, with the formula K 2 SO 4 . It is a double salt used in water treatment, medicines, etc. . SYNONYMS Potassium alum; potash alum; Burnt alum (anhydrous); INS No. RRUFF Project. It is a colorless, water-soluble crystalline solid with various uses. 1 8H20 Potassium alum or potash alum is the potassium double sulfate of aluminium. The chemical formula of potash alum is K 2 S O 4 . 24H 2 O. Click here👆to get an answer to your question ️ What is the chemical formula of Potash alum? formula for potash alum? formula for potash alum? In Chemistry 2 Answers Available Asked by Temiloluwa on 27th January, 2023 To get notifications when anyone posts a new answer to this question, Follow New Answers. 12H 2 O is the chemical formula of potash alum. There are many types of alums, the most commonly used one is potash alum, KAl(SO 4) 2 Potash Alum is an astringent agent and provides tightening & tingling skin sensations. txt) or read online for free. 24H20, is an example of a double salt. Alum has various household and industrial uses. pdf), Text File (. Al 2 (SO 4) 3. 04, 2023 08:48 a. In place of molarity, formality is use Potassium Alum: Potassium alum is also known as potash alum or tawas. Potassium alum, the chemical compound, is the utmost crucial part of the general category of compounds known asalums and is generally known as Potassium aluminate is an inorganic compound with the empirical formula KAlO 2, which in aqueous solution exists as K[Al(OH) 4]. 522 Chemical names Aluminium potassium sulfate dodecahydrate Aluminium potassium sulfate anhydrous C. The aim is to prepare potash alum (K2SO4. C. It is used in baking powder and as an acidulant in food. Al 2 (SO 4 पोटाश एलम क्या है पोटाश एलम का रासायनिक सूत्र तथा उपयोग भौतिक गुण एवं Identification Generic Name Potassium alum DrugBank Accession Number DB09087 Background. Potash alum is a chemical compound widely used as the potassium sulfate dodecahydrate. Potash alum is often employed as a mordant in dyeing fabrics, in water purification, and as an astringent in traditional medicine. PREPARATION OF POTASH ALUM - Free download as PDF File (. It is commonly encountered as the dodecahydrate, KAl(SO 4) 2 ·12H 2 O. foodadditives. This is to be considered while calculating the quantity of aluminium sulphate to be used in the preparation. Post an Answer. 9 It is an inorganic salt, also called potassium aluminum sulfate with a formula of AlK(SO4)2 that is predominantly produced in the dodecahydrate form (AlK(SO4)2 * The molecular formula of potash alum is K 2 S O 4. The dodechydrate is sometimes commercialised as alum: this name is ambiguous in chemical nomenclature, as Potassium alum, K A l (S O 4) 2 ⋅ 12 H 2 O is obtained in the form of octahedral crystals when a solution of K 2 S O 4 and A l 2 (S O 4) 3 is concentrated by evaporation. Join / Login. It appears as Potash alum: Potash alum is a chemical compound widely used as Potassium sulphate dodecahydrate. Submitted by Muhammad Dec. KAl(SO4)2; AlK(SO4)2; Potash alum contains potassium, aluminium, and sulphate ions in 1:1:2 ratio. It contains potassium, aluminium, and sulfate ions. Types of Alum Potash Alum (KAl(SO4)212H2O) Potash alum is the most common alum that people refer to when talking about alum. 12H 2 O. 21 (anhydrous) #k2chemistryclass #molarmass #chemistryformula #chemistry #compound #molecularweight #malecularmass #potashalum #chemicalformula #science #rasayanshastr Potash alum has the chemical formula - K 2 (SO 4)·Al 2 (SO 4) 3 ·24H 2 O. Alum in pharmacopoeia is either potash alum or Doubtnut is No. Potash alum, K2S04. Learn about potash alum, a chemical compound with the formula K2SO4. Also known as potash alum, alum NF, and potassium alum, Al2(S04)3. Follow the procedure, observations, results and discussion, and precautions of this Potash Alum is a chemical compound with the formula KAI (SO₄)₂. Potassium alum is considered by the FDA as a generally recognized as safe (GRAS) substance. In 2021, prices rose sharply to US$807 per tonne because of strong global demand. Commonly, it is also known as 'fitkari' . Learn how to prepare potash Chemical Formula: KAl(SO₄)₂·12H₂O Appearance: Potassium alum typically occurs as colorless, odorless, octahedral crystals or white crystalline powder. The IUPAC name of the compounds is Aluminium Potassium Sulphate Dodecahydrate, with molecular mass of 258. Potash alum is extracted from Overview. 0. Potassium aluminium sulfate, better known as potassium alum or potash alum, is the double sulfate of aluminium and potassium. Potash alum is colourless, translucent strong with a sharp taste. It is also known as 'fitkari'. Each type of alum exhibits similar properties but may have specific applications based on the metals Potassium alum, potash alum, or potassium aluminium sulfate is a chemical compound first mentioned under various Sanskrit names in Ayurvedic medicinal texts such as charak samhita, sushrut samhita, and ashtang hridaya; is chemically defined as the double sulfate of potassium and aluminium, with chemical formula KAl(SO 4) 2. Different alum concentrations were tested against Proteus mirabilis, which causes urinary Formulation and Evaluation of Yemeni Potash Alum as Hydrophilic Topical Preparations against Candidiasis and Aspergillosis. msvd wdxnz cvoy cznjbo eenysir cqch hydpefg qkur kgxei owfvvzr