Which of the following compounds is used as a fire extinguisher?

$A$ metal $(A)$ on heating in nitrogen gas gives compound $(B)$. $(B)$ on treatment with $H_{2}O$ gives a colourless gas which when passed through $CuSO_{4}$ solution gives a dark blue-violet coloured solution. $(A)$ and $(B)$ respectively,are

Which of the following is the most important factor in making lithium metal the strongest reducing agent?

When $NaOH$ crystals are left in open air,they acquire a fluid layer around each crystal because:

Match the following:

Compound	Molecular formula
$1$. Lime stone	$a$. $CaO$
$2$. Quick lime	$b$. $NaHCO_3$
$3$. Washing soda	$c$. $CaCO_3$
$4$. Baking soda	$d$. $Na_2CO_3 \cdot 10H_2O$

Which of the following statements is false for alkali metals?