A student forgot to add the reaction mixture to the round bottomed open flask at `27^(@) C` and put it on the flame After a lapse of time he realized his mistake using a pyrometer he found the temperature of the flask was `477^(@)C` What fraction of air would have been expelled out ? .

Explanation

Since the student was working in the laboratory, there is no change in pressure. Thus, Charles' Law is applicable.
According to given data : `V_(1) = V L ("say") , V_(2) = ?`
`T_(1) = 27 + 273 = 300 K , T_(2) = 477 + 273= 750 K`
`:. (V_(1))/(T_(1)) = (V_(2))/(T_(2))` or `V_(2) = (V_(1)T_(2))/(T_(1)) = ((V L ) xx (750 K))/((300 K)) = 2.5 V`
Thus, volume of air expelleed `= 2.5 V - V = 1.5 V`
Fraction of air expelled `= (1.5 v)/(2.5 V) = 3/5`