What products are formed when $1 \ mol$ of calcium phosphide reacts with an excess of water?

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 :

Which of the following does not dissolve in dil $H_2SO_4$?

Identify the reactions in which,upon heating,a diatomic gas is evolved,leaving behind a metallic residue.
$(A)$ $2NaN_{3(s)} \xrightarrow{\Delta} 2Na_{(s)} + 3N_{2(g)}$
$(B)$ $Ni(CO)_{4(g)} \xrightarrow{250^{\circ}C} Ni_{(s)} + 4CO_{(g)}$
$(C)$ $2KClO_{3(s)} \xrightarrow{\Delta} 2KCl_{(s)} + 3O_{2(g)}$
$(D)$ $2HgO_{(s)} \xrightarrow{\Delta} 2Hg_{(l)} + O_{2(g)}$
$(E)$ $NH_{4}NO_{2(s)} \xrightarrow{\Delta} N_{2(g)} + 2H_{2}O_{(g)}$

Match the following:

Metal	Uses
$1$. Sodium	$a$. For preparing springs
$2$. Beryllium-copper	$b$. In treatment of cancer
$3$. Radium	$c$. In preparation of aeroplanes
$4$. Magnesium-aluminium	$d$. In color industries

An alloy which does not contain copper is