In a metal deficient oxide sample,$M_X Y_2 O_4$ ($M$ and $Y$ are metals),$M$ is present in both $+2$ and $+3$ oxidation states and $Y$ is in $+3$ oxidation state. If the fraction of $M^{2+}$ ions present in $M$ is $\frac{1}{3}$,the value of $X$ is. . . . . . .

$5.75 \ mg$ of sodium vapour is converted to sodium ion. If the ionisation energy of sodium is $490 \ kJ \ mol^{-1}$ and atomic weight is $23 \ g \ mol^{-1}$,the amount of energy needed for this conversion will be (in $kJ$)

In the combustion of $2.0 \ g$ of methane,$25 \ kcal$ of heat is liberated. The heat of combustion of methane would be ..... $kcal$.

$6.023 \times 10^{22}$ molecules are present in $10 \ g$ of a substance $'x'.$ The molarity of a solution containing $5 \ g$ of substance $'x'$ in $2 \ L$ solution is.......... $\times 10^{-3}$

At $T \ K$,$100 \ L$ of dry oxygen is present in a sealed container. It is subjected to silent electric discharge,until the volumes of oxygen and ozone become equal. What is the volume (in litres) of ozone formed at $T \ K$?

Consider the reaction shown below. The percentage yield of the amide product is $......$ . (Round off to the Nearest Integer). (Given: Atomic mass: $C = 12.0 \, u, H = 1.0 \, u, N = 14.0 \, u, O = 16.0 \, u, Cl = 35.5 \, u$)
$C_6H_5COCl + (C_6H_5)_2NH \rightarrow C_6H_5CON(C_6H_5)_2 + HCl$
Given: $0.140 \, g$ of $C_6H_5COCl$ reacts with $0.388 \, g$ of $(C_6H_5)_2NH$ to produce $0.210 \, g$ of $C_6H_5CON(C_6H_5)_2$.