Which of the following compounds has a positive enthalpy of solution?

(1) LiF                                       

 (2) LiCl

(3) LiBr                                       

(4) Lil

Which of the following metal on burning in moist air does not give the smell of ammonia?

1. Mg                               

2. Ca

3. K                                 

4. Li

Among the carbonates of alkali metals which one has highest thermal stability?

(1) $C{s}_{2}C{O}_3$                 

(2) $R{b}_{2}C{O}_3$                     

(3) $K_{2}C{O}_3$                   

(4) $N{a}_{2}C{O}_3$

Incorrect statement is:

(a)$NaHC{O}_3$ and $KHC{O}_3$ have same crystal structure

(b) On heating $LiN{O}_3$ decomposes into $L{i}_{2}O$ and $N{O}_2$

(c) Among alkali metals, Li metal impart red colour to flame 

(d) $L{i}_{2}S{O}_4$ does not form alum 

The solubility of metal halides depends on their nature, lattice enthalpy and hydration enthalpy of the individual ions. Amongst fluorides of alkali metals, the lowest solubility of LiF in water is due to:

(1) Ionic nature of lithium fluoride             

(2) High lattice enthalpy

(3) High hydration enthalpy of lithium ion

(4) Low ionisation enthalpy of lithium atom

The strongest factor responsible for reducing action of Li metal in an aqueous solution is :

1. Sublimation enthalpy .         

2. Ionisation enthalpy.

3. Hydration enthalpy .             

4. Electron-gain enthalpy.

The effect of addion of gypsum to cement is-

1. It reduces the setting time of cement .    

2. The setting time of cement increases.

3. The colour of cement becomes light .          

4. A shining surface is obtained.

A compound (A) is used in the preparation of washing soda to recover ammonia in Solvay's process. When CO₂ is bubbled through an aqueous solution of (A), the solution turns milky. It is used in whitewashing due to its disinfectant nature. The chemical formula of A is : 

1. $\mathrm{Ca}{\left({\mathrm{HCO}}_3\right)}_2$                       

2. CaO

3. $\mathrm{Ca}{\left(\mathrm{OH}\right)}_2$                           

4. ${\mathrm{CaCO}}_3$

Which of the following statement about the sulphate of alkali metal is correct?

1. Expect $L{i}_{2}S{O}_4$ all sulphate of other alkali metals are soluble in hot water

2. All sulphate salts of alkali metals except lithium sulphate forms alum.

3. All sulphate salts of alkali metals except lithium sulphate do not decompose at high temperature 

4. All of the above

When a standard solution of NaOH is left in air for a few hours :

(1) a precipitate will form

(2) strength of solution will decrease

(3) the strength of solution will increase

(4) the concentration of $N{a}^{+}.$ion in solution will remains same