\(50cm^{3}\) of hydrogen are sparked with \(20cm^{3}\) of oxygen at \(100°C\) and \(1atm\) . The total volume of the residual gases in

A.

50 cm3

B.

10 cm3

C.

40 cm3

D.

30 cm3

E.

70 cm3

Correct answer is A

The equation of the reaction is:

\(2H_{{2}{(g)}} + O_{{2}{(g)}} = 2H_{2}O_{(g)}\)

Before Sparking we have : \(50cm^{3} : 20cm^{3}\)

On Sparking, \(40cm^{3} : 20cm^{3} : 40cm^{3}\)

After Sparking, we have \(10cm^{3} : 0  : 40cm^{3}\)

Hence, the volume of residual gases = \((10+40)cm^{3} = 50cm^{3}\)