Question

An aqueous solution of X is added slowly to an aqueous solution of Y as shown in List I. The variation in conductivity of these reactions is given in List II. Match List I with List II and select the correct option using the code given below the lists:
$\begin{array}{cc}\text{List I}& \text{List II}\\ \left(A\right)(C_2{H}_5{)}_{3}N+C{H}_{3}COOH& \text{(P) Initially conductivity decreases and then increases}\\ XY& \\ \left(B\right)KI\left(0.1M\right)+AgN{O}_3\left(0.01M\right)& \text{(Q) Initially conductivity decreases and then does not change much}\\ XY& \\ \left(C\right)C{H}_{3}COOH+KOH& \text{(R) Initially conductivity increases and then does not change much}\\ XY& \\ \left(D\right)NaOH+HI& \text{(S) Initially conductivity does not change much and then increases}\\ XY& \end{array}$
Which of the following is the only correct combination?

• A. A-R; B-S; C-Q; D-P
• B. A-S; B-R; C-Q; D-P
• C. A-Q; B-R; C-S; D-P
• D. A-P; B-S; C-R; D-Q

Answer 1

The correct option is A A-R; B-S; C-Q; D-P

Solutions of strong electrolytes has good conductivity and solutions of weak electrolyte has poor conductivity.

$\left(A\right)(C_2{H}_5{)}_{3}N+C{H}_{3}COOH$
$XY$
(R) Since a weak base is added to a weak acid, the conductivity increases due to formation of the salt triethylammonium acetate and then does not change much after neutralization.


$\left(B\right)KI\left(0.1M\right)+AgN{O}_3\left(0.01M\right)$
$XY$
(S) Due to the formation of solid $AgI$, the conductivity does not change much initially and once all the $AgN{O}_3$ is consumed then conductivity increases due to the excess $KI$.


$\left(C\right)C{H}_{3}COOH+KOH$
$XY$
(Q) Since a weak acid is added to a strong base, the conductivity decreases due to the consumption of strong base initially and then does not change much after neutralization.


$\left(D\right)NaOH+HI$
$XY$
(P) Since a strong base is added to an acid, the conductivity decreases due to the consumption of strong acid and then after neutralization it increases.