Question

A constant pressure air thermometer gave a reading of 47.5 units of volume when immersed in ice cold water, and 67 units in a boiling liquid. The boiling point of the liquid will be

• A. $ 135{}^\circ C $
• B. $ 125{}^\circ C $
• C. $ 112{}^\circ C $
• D. $ 100{}^\circ C $

Answer 1

Answer: (C)

Initial volume $ ~{{V}_{1}}=47.5\,\,unit $ Temperature of ice cold water $ {{T}_{1}}={{0}^{o}}C=273\,\,K $ Final volume of $ {{V}_{2}}=67\,\,unit $ Applying Charles law, we have $ \frac{{{V}_{1}}}{{{T}_{1}}}=\frac{{{V}_{2}}}{{{T}_{2}}} $ (where temperature $ {{T}_{2}} $ is the boiling point) or $ {{T}_{2}}=\frac{{{V}_{2}}}{{{V}_{1}}}\times {{T}_{1}}=\frac{67\times 273}{47.5} $ $ =385K={{112}^{o}}C $