The pair of compounds which do not exist in solution together?

(1) NaHCO₃ and NaOH

(2) NaHCO₃ and H₂O

(3) NaHCO₃ and Na₂CO₃

(4) Na₂CO₃ and NaOH

Among the following, the most basic oxide is                    [KVPY SA 2012]

(1) Al₂O₃

(2) SiO₂

(3) P₂O₅

(4) Na₂O

Which element does not form alum?

1.  Fe

2.  Li

3.  K

4.  Al

Sodium carbonate exists as

(1) Na₂CO₃.10H₂O(s)

(2) Na₂CO_3.H₂O(s)

(3) Na₂CO₃

(4) In all forms its a matter of temperature

Which of the following order is correct?

(1) LiCl<NaCl<KCl (solubility in water)

(2) BaO>SrO>CaO (acidic nature)

(3) MgCl₂<MgBr₂<MgI₂ (Solubility in acetone)

(4) Li₂CO₃>Na₂CO₃>K₂CO₃ (thermal stability)

Which of the following represents probable order of mobility of ions in aqueous solution?

(1) Be²⁺<Mg²⁺<Na⁺<K⁺

(2) Be²⁺>Mg²⁺>Na⁺>K⁺

(3) Na⁺>K⁺>Be²⁺>Mg²⁺

(4) Na⁺<K⁺<Be²⁺<Mg²⁺

Which of the following statements regarding Be is incorrect?

(1) It forms ionic compounds almost exclusively, even with the highly electronegative elements

(2) It does not form ionic compounds containing simple Be²⁺ ion, but does readily achieve a maximum co-ordination number of four through formation of complex ions such as BeF₄ and [Be(H₂O)₄]²⁺

(3) It forms a series of organo derivatives BeR₂ and [BeR₃], which contain covalent Be-C bonds

(4) Its halides are covalent polymers that are readily hydrolysed or cleaved by donors

CO₂ gas along with solid (y) is obained when sodium salt (x) is heated. (x) is again obtained when CO₂ gas is passed into aqueous solution of (y), (x) and (y) are

(1) Na₂CO₃.Na₂O

(2) Na₂CO₃, NaOH

(3) NaHCO₃, Na₂CO₃

(4) NaCO₃, NaHCO₃

A substance that gives a brick red flame and breaks down on heating giving oxygen and a brown gas is-

1. Calcium carbonate.

2. Magnesium carbonate.

3. Magnesium nitrate.

4. Calcium nitrate.

A chemical compound A is used for water softening to remove temporary hardness. A reacts with Na₂CO₃ to form caustic soda. When CO₂ is bubbled through A it becomes cloudy. The chemical formula of A is

(1) CaO

(2) Ca(OH)₂

(3) Ca(HCO₃)₂

(4) CaCO₃