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 $$\mathrm{CH}_{2} \mathrm{Cl}_{2}(\mathrm{DCM})$$. The concentration of $$\mathrm{DCM}$$ is ___________ ppm (by mass).

Given :

atomic mass : C = 12

H = 1

Cl = 35.5

density of $$\mathrm{CHCl}_{3}=1.49 \mathrm{~g} \mathrm{~cm}^{-3}$$

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

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

When 0.01 mol of an organic compound containing 60% carbon was burnt completely, 4.4 g of CO$$_2$$ was produced. The molar mass of compound is _____________ g mol$$^{-1}$$ (Nearest integer).

Number of hydrogen atoms per molecule of a hydrocarbon A having 85.8% carbon is __________

(Given : Molar mass of A = 84 g mol$$^{-1}$$)