Sodium metal reacts with $Al_2O_3$ at high temperature to give a sodium compound $X$. Compound $X$ reacts with $CO_2$ in water to give $Y$. What is $Y$?

In the expansion of $(1+x)^n$,the coefficients of $p$-th and $(p+1)$-th terms are respectively $p$ and $q$. Then $p+q=$

If $u=\sin ^{-1}\left(\frac{x^2+y^2}{x+y}\right)$ then $x \frac{\partial u}{\partial x}+y \frac{\partial u}{\partial y}$ is equal to:

Two cylinders $A$ and $B$ fitted with pistons,contain equal number of moles of an ideal monoatomic gas at $400 ~K$. The piston of $A$ is free to move while that of $B$ is held fixed. Same amount of heat energy is given to the gas in each cylinder. If the rise in temperature of the gas in $A$ is $42 ~K$,the rise in temperature of the gas in $B$ is $(\gamma = 5/3)$. (in $~K$)

An ideal coil of $10\, H$ is connected in series with a resistance of $5\, \Omega$ and a battery of $5\, V$. After $2\, s$,after the connection is made,the current flowing (in ampere) in the circuit is.

Which of the following is not a Lewis acid?