H2 + I2 -------- 2HI (an elementary reaction)

Initial rate=R

if the volume of the container containing the gaseous mixture is increased 2 times, then find the rate of reaction ?

rate of reaction will become 1/4 times...... as order of the rxn is 2 ... rate = k [ H2 ] [ I2 ] .... concentration is moles / volume..... if we increase the volume by 2 times than the concentration will become 1/ 4 therefore rate of the rxn will become 1/4 times...