An alloy which does not contain copper is

$A$ metal $M$ and its compound can give the following observable changes in a sequence of reactions: $M$ $\xrightarrow{\text{dilute } HNO_3} \text{Colourless solution}$ $\xrightarrow{\text{aqueous } NaOH} \text{White precipitate}$ $\xrightarrow{\text{excess } NaOH_{(aq)}} \text{Colourless solution}$ $\xrightarrow{H_2S} \text{White precipitate}$. Identify the metal $M$.

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: $KF > KCl > KBr > KI$

For a good quality cement,the ratio of lime to the total of the oxides of $Si$,$Al$ and $Fe$ should be as close as to :

Arrange the following in the correct order of thermal stability:
$K_2CO_3, MgCO_3, CaCO_3, BeCO_3$

Match the average fundamental compounds with their proper percentage present in Portland cement.

Compound	Percentage proportion
$1. CaO$	$d. 50-60\%$
$2. Al_2O_3$	$a. 5-10\%$
$3. SO_3$	$b. 1-3\%$