Introduction to Reversible and Irreversible Reactions

Q. Consider the following reactions in which all the reactants and products are in gaseous state.
$2PQ\leftrightharpoons P_2+Q_2;K_1=2.5\times {10}^5$
$PQ+\frac{1}{2}{R}_2\leftrightharpoons PQR,K_2=5\times {10}^{-3}$

The value of K₃ for the equilibrium
$1/2P_2+1/2Q_2+1/2R_2\leftrightharpoons PQR$

1. $2.5\times {10}^{-3}$
2. $2.5\times {10}^3$
3. $1.0\times {10}^{-5}$
4. $5\times {10}^3$

Q. Consider the general hypothetical reaction:
$A\left(s\right)\leftrightharpoons 2B\left(g\right)+3C\left(g\right)$
If the concentration of C at equilibrium is doubled, then after the equilibrium is re-established, the concentration of B will be :

1. Twice of its original value
2. Half of its original value
3. $2\sqrt{2}$ times of original value
4. $\frac{1}{2\surd 2}$ times the original value

Q.

A reversible reaction is one which :

1. Proceeds in one direction

2. Proceeds spontaneously

3. Proceeds in both directions

4. None of the above

Q.

For the reaction $PC{l}_5$ (g) $\leftrightharpoons$ $PC{l}_3$ (g) + $C{l}_2$ (g) if we start with only a moles of $PC{l}_5$
$\begin{array}{cccc}& PC{l}_5& PC{l}_3& C{l}_2\left(g\right)\\ Molest=0& a& 0& 0\\ MolesAtEq.& a(1-\alpha )& a\alpha & a\alpha \end{array}$
$\alpha$ is called the degree of dissociation - True or false?

1. True

2. False

Q.

$C{H}_{3}COOH\left(l\right)+C_2{H}_{5}OH\left(l\right)\rightleftharpoons C{H}_{3}COO{C}_2{H}_5\left(l\right)+H_{2}O\left(l\right)$

In the above reaction, one mole of each of acetic acid and alcohol are heated in the presence of

little conc. $H_{2}S{O}_4$. On equilibrium being attained

1. 1 mole of ethyl acetate is formed

2. 2 mole of ethyl acetate are formed

3. $\frac{1}{2}$ moles of ethyl acetate is formed

4. $\frac{2}{3}$ moles of ethyl acetate is formed