Chemistry Quiz on Acids and Bases

What is the pH range of acids?

• 0-7

• 7-14

• 7 only

• 14 only

Answer explanation

The pH scale ranges from 0 to 14. Acids have a pH less than 7, indicating higher concentrations of hydrogen ions. Therefore, the correct range for acids is 0-7.

Which of the following turns blue litmus red?

• Acids

• Bases

• Salts

• Water

Answer explanation

Acids turn blue litmus paper red due to their ability to donate protons (H+ ions) in solution, which changes the color of the indicator. Bases turn red litmus blue, while salts and water do not affect litmus color.

What is the pH of a neutral solution?

• 0

• 7

• 14

• 1

Answer explanation

A neutral solution has a pH of 7, which indicates a balance between hydrogen ions (H+) and hydroxide ions (OH-). Values below 7 are acidic, while values above 7 are basic.

Which of the following is used as an antacid?

• HCl

• NaOH

• Mg(OH)2

• H2SO4

Answer explanation

Mg(OH)2, or magnesium hydroxide, is commonly used as an antacid to neutralize stomach acid. The other options, HCl and H2SO4, are acids, while NaOH is a strong base, making Mg(OH)2 the correct choice.

What is the chemical formula for baking soda?

• NaCl

• NaHCO3

• Na2CO3

• CaO

Answer explanation

The chemical formula for baking soda is NaHCO3, which consists of sodium (Na), hydrogen (H), carbon (C), and three oxygen (O) atoms. The other options represent different compounds.

Which of the following is an example of a strong acid?

• Acetic acid

• Hydrochloric acid

• Carbonic acid

• Citric acid

Answer explanation

Hydrochloric acid is a strong acid, fully dissociating in water to release hydrogen ions. In contrast, acetic, carbonic, and citric acids are weak acids, only partially dissociating.

What is the main use of bleaching powder?

• As a fuel

• As a fertilizer

• For bleaching and disinfecting

• As a building material

Answer explanation

Bleaching powder, primarily calcium hypochlorite, is mainly used for bleaching and disinfecting due to its strong oxidizing properties. It effectively kills bacteria and is commonly used in water treatment and sanitation.

What is the chemical name of washing soda?

• Sodium chloride

• Sodium carbonate

• Sodium bicarbonate

• Sodium hydroxide

Answer explanation

Washing soda is chemically known as sodium carbonate (Na2CO3). It is commonly used in cleaning products and differs from sodium chloride (table salt), sodium bicarbonate (baking soda), and sodium hydroxide (lye).

Which of the following is used to test the pH of a solution?

• Litmus paper

• Phenolphthalein

• Universal indicator

• All of the above

Answer explanation

All of the options—litmus paper, phenolphthalein, and universal indicator—are used to test the pH of a solution. Therefore, the correct answer is 'All of the above'.

What is the pH range of bases?

• 0-7

• 7-14

• 7 only

• 0 only

Answer explanation

The pH scale ranges from 0 to 14. A pH of 7 is neutral, while values above 7 indicate basic (alkaline) substances. Therefore, the correct range for bases is 7-14.