Select the correct order of solubility (in water) from the following:

1. SrSO₄ < CaSO₄ < MgSO₄ < BeSO₄

2. NaF < KF < RbF < CsF

3. Ba(OH)₂ > Sr(OH)₂ > Ca(OH)₂ > Mg(OH)₂

4 All of the above

Which of the following compounds has the lowest melting point?

1. CaBr₂

2. CaI₂

3. CaF₂

4. CaCl₂

The correct order of increasing thermal stability of K₂CO₃, MgCO₃, CaCO₃ and BeCO₃ is:
(1) BeCO₃ < MgCO₃ < K₂CO₃ < CaCO₃

(2) BeCO₃ < MgCO₃ < CaCO₃ < K₂CO₃

(3) MgCO₃ < BeCO₃ < CaCO₃ < K₂CO₃

(4) K₂CO₃ < MgCO₃ < CaCO₃ < BeCO₃

Which of the following compounds has a higher hydration energy than the lattice energy?

1. BaSO₄                           

2. MgSO₄

3. CaSO₄                           

4. SrSO₄

The incorrect order of lattice energy among the following set is:

1. ${\mathrm{AlF}}_3>{\mathrm{MgF}}_2$         

2. ${\mathrm{Li}}_3\mathrm{N}>{\mathrm{Li}}_2\mathrm{O}$

3. $\mathrm{NaCl}>\mathrm{LiF}$           

4. $\mathrm{TiC}>\mathrm{ScN}$