Question

Temperature remaining constant, the pressure of gas is decreased by $20\%$ . The percentage change in volume

• A. increases by $20\%$
• B. decreases by $20\%$
• C. increases by $25\%$
• D. decreases by $25\%$

Answer 1

Answer: (C)

According to Boyle's law
$p_1{V}_1=p_2{V}_2$
As the pressure is decreased by $20\%$, therefore
$P_2=\frac{80}{100}{p}_1$
$p_1{V}_1=\frac{80}{100}{p}_1{V}_2$
$V_1=\frac{80}{100}{V}_2$
$\therefore$ Percentage increase in volume
$=\frac{V_2-V_1}{V_1}\times 100$
$=\frac{100-80}{80}\times 100$
$=25\%$