Question

Assertion: Potassium bromide (KBr) is a strong electrolyte.
Reason: Potassium bromide completely dissociates in water.
A. If both assertion and reason are correct and reason is the correct explanation of assertion.
B. If both assertion and reason are correct and reason is not the correct explanation of assertion.
C. If the assertion is correct but the reason is incorrect.
D. If the assertion is incorrect but the reason is correct.

Answer 1

The solution that conducts electricity is known as electrolyte. The salt which easily dissociates to form ions is known as strong electrolyte. The salt which does not dissociate easily to form ions is known as weak electrolyte.

Complete step-by-step solution: The substance can be acids, bases or salts which on dissolving in water dissociated forming ions and producing electricity is known as an electrolyte. Electrolyte forms ions, so conducts electricity.

Electrolytes are of two types:
1. Weak Electrolyte
2. Strong Electrolyte

Weak electrolyte- The electrolytes that do not dissociate completely in an aqueous solution are known as a weak electrolyte.Weak electrolytes dissociate partially, so the solution of weak electrolytes contain ions as well as un-dissociated molecules.Weak acids or bases form weak electrolytes.

Strong electrolyte- The electrolytes that dissociate completely in an aqueous solution are known as a strong electrolyte.The solution of strong electrolyte contains ions only. Strong acids or bases form strong electrolytes.

Potassium bromide is an ionic and polar compound, so it dissociates into ions in water easily.So, it is true that potassium bromide (KBr) is a strong electrolyte and it completely dissociates in water.

The dissociation of potassium bromide is shown as follows:
${\text{KBr}}\, \to \,{{\text{K}}^{{\text{ + }}\,}} + \,{\text{B}}{{\text{r}}^ - }$

Therefore, option (A) If both assertion and reason are correct and reason is the correct explanation
of assertion, is correct.

Note: The acid or base which easily gives hydrogen or hydroxide ions are known as strong acid or base, so strong acid or base dissociates completely hence are known as a strong electrolyte. The acid or base which hardly gives hydrogen or hydroxide ions are known as weak acid or base, so weak acid or base does not dissociate completely hence are known as a weak electrolyte.