Assertion : In electrochemical cell, we cannot use $\mathrm{KCI}$ in the salt bridge if anodic or cathodic

                  compartment consists of ${\mathrm{Ag}}^{+}$ of ${\mathrm{Pb}}^{2+}$ ion.

Reason : Salt bridge is employed to maintain the electrical neutrality and to minimize the liquid-liquid

               junction potential.

Assertion : Fluorine cannot be prepared from fluorides by chemical oxidation.

Reason : Fluorine is the strongest oxidizing agent due to its highly positive standard potential.

Assertion : : Sodium reacts with water at room temperature, whereas magnesium decomposes only hot water.

Reason : Sodium is more electropositive than magnesium.

Assertion : Silver nitrate solution becomes bluish when copper rod is placed in it.

Reason : Copper is more electropositive than silver.