Which one of the following alkali metals forms only the normal oxide M₂O on heating in air?

1. Rb

2. K

3. Li

4. Na

Which of the following biologically important ions is also a constituent of the sodium pump?

1. Ca²⁺
2. Mg²⁺
3. K⁺
4. Fe²⁺

Match List I with List II for the composition of substances and select the correct answer using the code given below:

Code :

A compound that has higher hydration enthalpy than the lattice enthalpy is: 

1. ${\mathrm{CaSO}}_4$

2. ${\mathrm{BeSO}}_4$

3. ${\mathrm{BaSO}}_4$

4. ${\mathrm{SrSO}}_4$

Solubility of alkaline earth metal sulphates in water decreases in the sequence:

1. Mg > Ca > Sr >Ba
2. Ca > Sr > Ba > Mg
3. Sr > Ca > Mg > Ba
4. Ba > Mg > Sr > Ca

Among the given options, what is the property of the alkaline earth metals that increases with their atomic number?
1. Solubility of their hydroxides in water
2. Solubility of their sulphates in water
3. Ionization energy
4. Electro-negativity

 An active ingredient in bleaching powder that aids in the bleaching action is:

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

2.  ${\mathrm{CaO}}_2\mathrm{Cl}$

3.  ${\mathrm{CaCl}}_2$

4.  ${\mathrm{CaOCl}}_2$

In replacement reaction 

The reaction will be most favorable if M happens to be:

1.  K
2.  Rb
3.  Li
4.  Na

A compound that releases CO₂ most easily upon heating is?
1. $K_{2}C{O}_3$
2. $N{a}_{2}C{O}_3$
3. $MgC{O}_3$
4. $CaC{O}_3$