Reactions of Acids with Metals

The video tutorial explains how acids react with surfaces and metals, using lemon juice as an example of an acidic substance that can cause stains. It then demonstrates an experiment where zinc granules react with dilute hydrochloric and sulfuric acids, releasing hydrogen gas. The presence of hydrogen is confirmed by a pop sound when a lit matchstick is introduced to the gas. The video provides chemical equations for these reactions and suggests trying similar experiments with other metals like iron, emphasizing safety precautions when handling acids.

What causes lemon juice to leave a stain on surfaces?

• It is oily.

• It is sticky.

• It is acidic.

• It is sweet.

What materials are needed for the experiment with zinc and acids?

• Zinc granules, baking soda, and a matchbox

• Zinc granules, vinegar, and a matchbox

• Zinc granules, dilute hydrochloric acid, dilute sulfuric acid, and a matchbox

• Zinc granules, water, and a matchbox

What observation indicates the presence of a gas when zinc reacts with acids?

• A gas is released.

• The solution becomes cold.

• The solution changes color.

• The solution becomes thick.

What sound is heard when a lit matchstick is brought near the gas released in the experiment?

• A hissing sound

• A pop sound

• A crackling sound

• No sound

What gas is released when a metal reacts with an acid?

• Oxygen

• Carbon dioxide

• Nitrogen

• Hydrogen

What is the product formed when zinc reacts with hydrochloric acid?

• Zinc carbonate

• Zinc nitrate

• Zinc chloride

• Zinc oxide