Question

During the reaction of some metals with dilute hydrochloric acid, following observations were made:
i. silver metal does not show any change.
ii. the temperature of the reaction mixture rises when aluminium (Al) is added.
iii. the reaction of sodium metal is found to be highly explosive.
iv. some bubbles of a gas are seen when lead (Pb) reacted with the acid. Explain these observations giving suitable reasons.

Answer 1

i. Silver does not show any change because silver is less reactive than hydrogen. It cannot displace hydrogen from dilute hydrochloric acid.
ii. The reaction between aluminium and hydrochloric acid is exothermic. Thus,
temperature of the reaction mixture rises.
iii. Sodium is highly reactive metal. It reacts
with hydrochloric acid vigorously/ explosively forming hydrogen gas along with the releaseoflarge amount of heat.
iv. When lead (Pb) reacts with HCl, bubbles are seen duetoformation of hydrogen gas.