What is the nature of metal nitrates?

Which of the following order$(s)$ is/are correct?
$(A)$ Thermal stability: $BeSO_4 < MgSO_4 < CaSO_4 < SrSO_4$
$(B)$ Melting point: $NaCl > KCl > RbCl > CsCl$
$(C)$ Solubility: $LiOH < NaOH$
$(D)$ Lattice energy: $KF > KCl > KBr > KI$

Which of the given orders is not correct?

The correct solubility order is/are:
$I. CaCO_3 > SrCO_3 > BaCO_3$
$II. Li_2CO_3 < Na_2CO_3 < K_2CO_3$
$III. K_2CO_3 < Rb_2CO_3 < Cs_2CO_3$
$IV. Na_2CO_3 > K_2CO_3 > Rb_2CO_3$

Match the following substances in List-$I$ with their uses in List-$II$:
| List-$I$ (Substance) | List-$II$ (Use) |
| :--- | :--- |
| $(A)$ $Na_2O_2$ | $(I)$ Photoelectric cells |
| $(B)$ $D_2O$ | $(II)$ Antacid |
| $(C)$ $Cs$ | $(III)$ Oxidising agent |
| $(D)$ $Mg(OH)_2$ | $(IV)$ Moderator |

Which of the following is the main component of Portland cement (besides lime)?