States of Matter Solid, Liquid and Gas MCQ Questions & Answers in Physical Chemistry | Chemistry

$${\text{The reaction between aluminium}}$$       $${\text{and caustic soda}}\,\,{\text{is}}$$
$$\mathop {2Al}\limits_{2 \times 27 = 54\,g} + 2NaOH + 2{H_2}O$$       $$ \to \mathop {2NaAl{O_2} + 3{H_2}}\limits_{3 \times 22.4\,L\,\,{\text{at}}\,\,STP} $$
$$\therefore \,\,54\,g\,\,{\text{of}}\,\,Al\,\,{\text{produces}}\,\,{H_2}\,\,{\text{at}}\,\,STP$$       $$ = 3 \times 22.4\,L$$
$$0.15\,g\,\,{\text{of}}\,\,Al\,\,{\text{will produce}}\,\,{H_2}\,\,{\text{at}}\,\,STP$$       $$ = \frac{{3 \times 22.4}}{{54}} \times 0.15 = 0.1867\,L$$
$$\eqalign{ & {\text{At}}\,\,STP\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,{\text{Given conditions}} \cr & {P_1} = 1\,atm\,\,\,\,\,\,\,\,\,\,\,\,\,{P_2} = 1\,\,bar = 0.987\,atm \cr & {V_1} = 0.186\,L\,\,\,\,\,\,\,\,\,{V_2} = ? \cr & {T_1} = 273\,K\,\,\,\,\,\,\,\,\,\,\,\,{T_2} = 273 + 20 = 293\,K \cr} $$
$${\text{Applying ideal gas equation,}}$$
$$\frac{{{P_1}{V_1}}}{{{T_1}}} = \frac{{{P_2}{V_2}}}{{{T_2}}};$$    $$\frac{{1 \times 0.1867}}{{273}} = \frac{{0.987 \times {V_2}}}{{293}}$$
$${V_2} = \frac{{293}}{{0.987}} \times \frac{{1 \times 0.1867}}{{273}}$$      $$ = 0.2030\,L = 203\,mL$$

Graphs of volume vs temperature at constant pressure are called isobars.

$$\eqalign{ & {u_{{N_2}}} = \sqrt {\frac{{3RT}}{M}} \cr & {\text{Mass of nitrogen atom}} \cr & = \frac{{{\text{Mass of nitrogen molecule}}}}{2} \cr & = \frac{M}{2} \cr & {u_{{N_2}}} = \sqrt {\frac{{3R\left( {2T} \right)}}{{\frac{M}{2}}}} \cr & \,\,\,\,\,\,\,\,\, = 2\sqrt {\frac{{3RT}}{M}} \cr & \,\,\,\,\,\,\,\,\, = 2{u_{{N_2}}} \cr} $$

In Frenkel defect, ions in solids dislocate from their positions. Hence, Frenkel defect is a dislocation defect.

$$\eqalign{ & {\text{Total equivalent of}} \cr & {C_2}{H_4} + C{O_2} + {H_2} \cr & = 0.2 + 0.2 + 0.2 \cr & = 0.6 \cr & {\text{Total moles of gases}} \cr & = \frac{{0.2}}{2} + \frac{{0.2}}{1} + \frac{{0.2}}{2} \cr & = 0.4 \cr & V = \frac{{nRT}}{P} \cr & \,\,\,\,\,\, = \frac{{0.4 \times 0.0821 \times 273}}{1} \cr & \,\,\,\,\,\, = 8.96\,L. \cr} $$

Particles of a gas collide in a straight line in all possible directions.

For ideal gas $$PV = nRT$$
Volume of $$1$$ $$mole$$  gas at $$1$$ $$atm$$  pressure and $$273\,K$$  is $$22.4\,L.$$

$$K\bar E = \frac{3}{2}\frac{n}{{{N_o}}}RT.$$    Average $$K\bar E$$  is the same for all gaseous molecules

Value of gas constant
$$\eqalign{ & \left( R \right)\, = 0.0821L\,atm\,{K^{ - 1}}mo{l^{ - 1}} \cr & = 8.314 \times {10^7}ergs\,{K^{ - 1}}\,mo{l^{ - 1}} \cr & = 8.314J{K^{ - 1}}mo{l^{ - 1}} = 1.987\,cal\,{K^{ - 1}}mo{l^{ - 1}} \cr} $$

$$F$$ - centres are the sites where anions are missing and instead electrons are present and the appearance of colour in solid alkali metal halides is generally due to $$F$$ - centres.