Question

Two gases A and B which react according to the equation $a{A}_{\left(g\right)}+b{B}_{\left(g\right)}\to c{C}_{\left(g\right)}+d{D}_{\left(g\right)}$ to give two gases C and D are taken (amount not known) in an Eudiometer tube (operating at a constant pressure and temperature) to cause the above. If on causing the reaction there is no volume change observed then which of the following statement are correct :

• A. $(a+b)=(c+d)$
• B. Average molecular mass may increase or decrease if either of A or B is present in limited amount.
• C. Vapour Density of the mixture will remain same throughout the course of reaction.
• D. Total moles of all the component of mixture will change.

Answer 1

Answer: (A), (C)

The correct options are
A $(a+b)=(c+d)$
C Vapour Density of the mixture will remain same throughout the course of reaction.

As total volume doesn't change so total no. of moles of gases initially and final are same. So, (a+b)=(c+d) .

And as no. of moles of gases in the mixture at any time is same so vapour density of the mixture will remain same throughout the course of the reaction.

Hence, option A and C are correct.