On heating quick lime with coke in an electric furnace,we get

Beryllium is placed above magnesium in Group $2$. What happens when beryllium powder is added to a solution of $MgCl_2$?

Match column $-I$ with column $-II$ :

Column $-I$	Column $-II$
$(a).$ Spodumene	$(p).$ $K$
$(b).$ Borax	$(q).$ $Na$
$(c).$ Sylvine	$(r).$ $Li$
$(d).$ Chile saltpetre	$(s).$ $Ca$

Which of the following is insoluble in excess of $NaOH$?

Identify the correct order of standard enthalpy of formation of sodium halides.

$A$ metal $X$ on heating in a stream of nitrogen gives $Y$. $Y$ on reaction with ${H_2}O$ gives a colorless gas which,when passed through a $CuSO_4$ solution,gives a blue color. What is $Y$?