Q.

Observe the following equilibrium in a 1 L flask. 

A(g)B(g)

At T(K), the equilibrium concentrations of A and B are 0.5 M and 0.375 M respectively. 0.1 moles of A is added into the flask and heated to T(K) to establish the equilibrium again. The new equilibrium concentrations (in M) of A and B are respectively  [2026]

1 0.742, 0.557  
2 0.557, 0.418  
3 0.367, 0.275  
4 0.53, 0.4  

Ans.

(2)

AB0.5 M0.375 M(At equilibrium)

Keq=[B]eq[A]eq=0.3750.5=0.75

Now 0.1 mole of A is added so reaction will move in forward direction.

AB0.6-x0.375+x

Keq=0.75=0.375+x0.6-x

0.45-0.75x=0.375+x

1.75x=0.075

x=0.0751.75=370=0.043

Moles of A=0.6-0.043=0.557

Moles of B=0.375+0.043=0.418

Ans. (2) is correct.