Pakistan MCQs

Litmus changes color depending on acidity or basicity.
Red litmus turns blue in bases, while blue litmus turns red in acids.

Acid and base properties cancel during neutralization.
The products commonly include a salt and water.

Antacids contain mild bases.
They reduce acidity and relieve symptoms such as heartburn.

The stomach secretes hydrochloric acid.
It helps activate digestive enzymes and kill many microbes.

Vinegar contains dilute acetic acid.
This acid gives vinegar its sour taste and preservative effect.

Citrus fruits such as lemons and oranges contain citric acid.
It contributes to their sour taste.

Muscle cells can produce lactate during anaerobic metabolism.
This supports short-term energy production when oxygen delivery is limited.

Acid-carbonate reactions form a salt, water, and carbon dioxide.
The gas causes visible bubbling.

Baking soda is sodium hydrogen carbonate, NaHCO₃.
It releases carbon dioxide when heated or mixed with acid.

The reaction produces carbon dioxide gas.
Gas bubbles become trapped and expand during heating.

Washing soda is hydrated sodium carbonate.
It is used for cleaning and softening water.

Bleaching powder releases chlorine-containing disinfecting agents.
It is used in water treatment and bleaching.