Find the oxidation state of sodium in $Na_{2}O_{2}$.

What is $Z$ in the following reaction? $CH_3-CH_2-CO_2^{\ominus} Na^{\oplus} \stackrel{NaOH / CaO}{\longrightarrow} Z$

$A$ uniform chain of length $L$ is lying on a horizontal table. If the coefficient of friction between the chain and the table top is $\mu$, what is the maximum length of the chain that can hang over the edge of the table without disturbing the rest of the chain on the table?

The foot of the perpendicular from $(0,2,3)$ to the line $\frac{x+3}{5}=\frac{y-1}{2}=\frac{z+4}{3}$ is

Which one of the following elements reacts with steam?

$A$ long solenoid of length $L$ has a mean diameter $D$. It has $n$ layers of windings of $N$ turns each. If it carries a current $i$,the magnetic field at its centre will be