Uracil is base present in $\mathrm{RNA}$  with the following structure. $\% \mathrm{of} \mathrm{N}$ in uracil is _______.

The number of units, which are used to express concentration of solutions from the following is _________.

(Mass percent, Mole, Mole fraction, Molarity, ppm, Molality.)

In sulphur estimation. $0.471 \mathrm{g}$ of an organic compound gave $1.4439 \mathrm{g}$ of barium sulphate. The percentage of sulphur in the compound is _______(Nearest Integer)

(Given: Atomic mass Ba: $137\mathrm{u}:\mathrm{S}:32\mathrm{u},\mathrm{O}:16\mathrm{u}$ )

The volume of $\mathrm{HCl}$, containing $73\mathrm{g} {\mathrm{L}}^{-1}$, required to completely neutralise $\mathrm{NaOH}$ obtained by reacting $0.69 \mathrm{g}$ of metallic sodium with water, is _____ $\mathrm{mL}$. (Nearest Integer)

(Given : molar Masses of $\mathrm{Na},\mathrm{Cl},\mathrm{O},\mathrm{H}$ are $23,35.5,16$ and $1\mathrm{g} {\mathrm{mol}}^{-1}$ respectively)

Some amount of dichloromethane $\left({\mathrm{CH}}_2{\mathrm{Cl}}_2\right)$ is added to $671.141\mathrm{mL}$ of chloroform $\left({\mathrm{CHCl}}_3\right)$ to prepare $2.6\times {10}^{-3}\mathrm{M}$ solution of ${\mathrm{CH}}_2{\mathrm{Cl}}_2\left(\mathrm{DCM}\right)$. The concentration of $\mathrm{DCM}$ is _____ ppm (by mass).

Given: Atomic mass : $\mathrm{C}=12;\mathrm{H}:1;\mathrm{Cl}=35.5$ density of ${\mathrm{CHCl}}_3=1.49\mathrm{g} {\mathrm{cm}}^{-3}$