PYQ Vault
EbooksTutor

New equilibrium amounts after adding a species to an equilibrium mixture

This type of question, asked 4 times: 6 Apr 2023, 23 Jan 2026 S2, 24 Jan 2026 S2, 28 Jan 2026 S2. All 4 questions below, oldest first.

Try each one first, then open its answer.

  1. Question 1

    6 Apr 2023

    142
    The equilibrium composition for the reaction PCl3+Cl2⇌PCl5PCl_{3}+Cl_{2}\rightleftharpoons PCl_{5} at 298 K298\text{ }K is given below.
    [PCl3]eq=0.2 mol L−1[Cl2]eq=0.1 mol L−1,[PCl5]eq=0.40 mol L−1\begin{matrix} \left\lbrack PCl_{3} \right\rbrack_{eq}= 0.2\text{ }mol{\text{ }L}^{- 1} & \left\lbrack Cl_{2} \right\rbrack_{eq}= 0.1\text{ }mol{\text{ }L}^{- 1}, \\ \left\lbrack PCl_{5} \right\rbrack_{eq}= 0.40\text{ }mol{\text{ }L}^{- 1} & \end{matrix}
    If 0.2 mol0.2\text{ }mol of Cl2Cl_{2} is added at the same temperature, the equilibrium concentrations of PCl5PCl_{5} is ____×10−2 mol L−1\times10^{- 2}\text{ }mol{\text{ }L}^{- 1}. Given: KcK_{c} for the reaction at 298 K298\text{ }K is 20

  2. Question 2

    23 Jan 2026 S2

    46
    X2(g)+Y2(g)⇌2Z(g)X_{2}(g) + Y_{2}(g) \rightleftharpoons 2Z(g) X2(g)X_{2}(g) and Y2(g)Y_{2}(g) are added to a 1 L flask and it is found that the system attains the above equilibrium at T(K)T(K) with the number of moles of X2( g),Y2( g)X_{2}(\text{ }g),Y_{2}(\text{ }g) and Z(g)Z(g) being 3, 3 and 9 mol respectively (equilibrium moles). Under this conditions of equilibrium, 10 mol of Z(g)Z(g) is added to the flask and the temperature is maintained at T(K)T(K). Then the number of moles of Z(g)Z(g) in the flask when the new equilibrium is established is ____\_\_\_\_ . (Nearest integer).

  3. Question 3

    24 Jan 2026 S2

    30
    Consider the following gaseous equilibrium in a closed container of volume "V" at T(K). P2( g)+Q2( g)⇌2PQ(g)P_{2}(\text{ }g) +Q_{2}(\text{ }g) \rightleftharpoons 2PQ\left( g \right) 2 moles each of P2( g),Q2( g)P_{2}(\text{ }g),Q_{2}(\text{ }g) and PQ(g)PQ(g) are present at equilibrium. Now one mole each of ' P2P_{2} ' and ' Q2Q_{2} ' are added to the equilibrium keeping the temperature at T(K)T(K). The number of moles of P2P_{2}, Q2Q_{2} and PQ at the new equilibrium, respectively, are -

    Tap an option to check your answer.

  4. Question 4

    28 Jan 2026 S2

    29
    Observe the following equilibrium in a 1 L flask.
    A(g)⇌B(g)A(g) \rightleftharpoons B(g)
    At T(K)T(K), the equilibrium concentrations of A and B are 0.5 M and 0.375 M respectively. 0.1 moles of A are added into the flask and heated to T(K)T(K) to establish the equilibrium again. The new equilibrium concentrations (in MM ) of AA and BB are respectively.

    Tap an option to check your answer.