Acids, Bases, & Neutralization

What ion does an Arrhenius acid produce in water?

• OH⁻

• Cl⁻

• H⁺

• Na⁺

Answer explanation

An Arrhenius acid produces H⁺ ions in water, which are responsible for the acidic properties of the solution. Therefore, the correct answer is H⁺.

Which of the following is a characteristic of bases?

• Sour taste

• Low pH

• Reacts with metals

• Slippery feel

Answer explanation

Bases are known for their slippery feel, which is a result of their ability to react with oils and fats. In contrast, acids typically have a sour taste, low pH, and can react with metals.

What is the pH range for acidic substances?

• 0–6

• 7

• 8–14

• 6–8

Answer explanation

The pH scale ranges from 0 to 14, where values from 0 to 6 indicate acidity. A pH of 7 is neutral, while 8 to 14 represents basic substances. Therefore, the correct range for acidic substances is 0–6.

What happens during a neutralization reaction?

• Acid reacts with metal to produce hydrogen gas

• Base reacts with fat to produce soap

• Base reacts with carbonate to produce carbon dioxide

• Acid reacts with base to produce water and salt

Answer explanation

During a neutralization reaction, an acid reacts with a base to produce water and salt. This is the defining characteristic of neutralization, distinguishing it from other reactions involving acids and bases.

Which of the following is an example of a base?

• NaOH

• Vinegar

• HCl

• Lemon juice

Answer explanation

NaOH, or sodium hydroxide, is a strong base that dissociates in water to produce hydroxide ions. In contrast, vinegar, HCl, and lemon juice are acidic substances, making NaOH the correct example of a base.

What color does litmus paper turn in the presence of an acid?

• Pink

• Red

• Clear

• Blue

Answer explanation

Litmus paper turns red in the presence of an acid. This is a standard test for acidity, where blue litmus paper changes to red when exposed to acidic solutions.

Which of the following substances is neutral with a pH of 7?

• Vinegar

• Ammonia

• Baking soda

• Water

Answer explanation

Water is the only substance listed with a neutral pH of 7. Vinegar is acidic, ammonia is basic, and baking soda is alkaline, making them not neutral.

What is the general equation for a neutralization reaction?

• Acid + Base → Water + Salt

• Acid + Metal → Hydrogen gas

• Acid + Carbonate → Carbon dioxide

• Base + Fat → Soap

Answer explanation

The general equation for a neutralization reaction is Acid + Base → Water + Salt. This describes the reaction where an acid and a base react to form water and a salt, which is the correct choice.

Which indicator turns pink in the presence of a base?

• Litmus paper

• Phenolphthalein

• pH paper

• Universal indicator

Answer explanation

Phenolphthalein turns pink in basic solutions, indicating a pH above 8.2. In contrast, litmus paper changes color at different pH levels, while pH paper and universal indicators provide a range of colors but do not specifically turn pink.

Why do acids and bases conduct electricity?

• They produce heat

• They form ions in water

• They react with metals

• They neutralize each other

Answer explanation

Acids and bases conduct electricity because they form ions in water. When dissolved, they dissociate into charged particles, allowing electric current to flow.