TNPSC Chemistry Acids, Bases and Salts Quiz 1

Concept Booster – TNPSC Chemistry Acids, Bases and Salts Quiz

Acids, Bases and Salts – Concept Booster

Acids, bases, and salts are common substances found in our daily lives. Understanding their properties, reactions, indicators, and pH values will help you answer important TNPSC Chemistry questions with confidence.

Q1. Substances that produce hydrogen ions (H⁺) in aqueous solution are called:

Acids are substances that release hydrogen ions (H⁺) when dissolved in water. According to the Arrhenius theory, the presence of hydrogen ions is responsible for the acidic properties of a solution. Acids are commonly found in foods, industrial chemicals, and laboratory reagents.

Key Points:

• Acids release H⁺ ions in water.
• Have a pH less than 7.
• Turn blue litmus red.
• Often have a sour taste.

Real-Life Example:

Lemon juice contains citric acid, which gives it a sour taste.

Answer: Acids

Q2. Substances that produce hydroxide ions (OH⁻) in aqueous solution are called:

Bases are substances that release hydroxide ions (OH⁻) when dissolved in water. These ions are responsible for the alkaline nature of the solution. Bases are commonly used in cleaning products and industrial processes.

Key Points:

• Bases release OH⁻ ions in water.
• Have a pH greater than 7.
• Turn red litmus blue.
• Usually have a bitter taste.

Real-Life Example:

Soap solution is basic and contains substances that produce hydroxide ions.

Answer: Bases

Q3. Which of the following is a strong acid?

A strong acid completely ionizes in water, producing a large number of hydrogen ions. Hydrochloric acid (HCl) is a strong acid commonly used in laboratories and industries.

Key Points:

• Completely ionizes in water.
• Produces many H⁺ ions.
• Has strong acidic properties.
• Example: HCl.

Real-Life Example:

Hydrochloric acid is naturally present in the human stomach and helps in digestion.

Answer: Hydrochloric acid

Q4. Which of the following is a base?

Bases are substances that produce hydroxide ions (OH⁻) when dissolved in water. Sodium hydroxide (NaOH) is a strong base commonly used in soap manufacturing, paper production, and cleaning products.

Key Points:

• Produces OH⁻ ions in water.
• Strong alkali.
• Turns red litmus blue.
• Used in industrial applications.

Real-Life Example:

Sodium hydroxide is used in the manufacture of soaps and detergents.

Answer: NaOH

Q5. The pH value of an acidic solution is:

The pH scale measures the acidity or basicity of a solution. Acidic solutions contain a higher concentration of hydrogen ions and have pH values below 7.

Key Points:

• pH less than 7 indicates acidity.
• More H⁺ ions present.
• Strong acids have very low pH.
• pH scale ranges from 0 to 14.

Real-Life Example:

Lemon juice has a pH of about 2, making it strongly acidic.

Answer: Less than 7

Q6. The pH value of a basic solution is:

Basic solutions contain hydroxide ions (OH⁻) and have pH values greater than 7. The higher the pH value, the stronger the base.

Key Points:

• pH greater than 7 indicates basic nature.
• Contains OH⁻ ions.
• Strong bases have high pH values.
• Opposite of acidic solutions.

Real-Life Example:

Soap solution has a pH greater than 7 and is basic in nature.

Answer: Greater than 7

Q7. A substance that changes color in acidic or basic solutions is called:

Indicators are substances used to determine whether a solution is acidic or basic. They show different colors depending on the pH of the solution.

Key Points:

• Used to test acids and bases.
• Changes color according to pH.
• Natural and synthetic indicators exist.
• Common examples include litmus and turmeric.

Real-Life Example:

Litmus paper is commonly used in laboratories to identify acids and bases.

Answer: Indicator

Q8. Which indicator turns red in acidic solution?

Litmus is a natural indicator obtained from lichens. Blue litmus paper turns red in the presence of an acid, indicating the acidic nature of the solution.

Key Points:

• Natural indicator.
• Blue litmus turns red in acid.
• Red litmus remains unchanged in acid.
• Commonly used in laboratories.

Real-Life Example:

When blue litmus paper is dipped in lemon juice, it turns red.

Answer: Litmus

Q9. Turmeric turns which color in a basic solution?

Turmeric is a natural indicator that remains yellow in acidic and neutral solutions but changes to reddish-brown in basic solutions.

Key Points:

• Natural indicator.
• Yellow in acids.
• Reddish-brown in bases.
• Obtained from turmeric powder.

Real-Life Example:

Applying soap solution to turmeric paper changes its color to reddish-brown.

Answer: Red

Q10. Which gas is produced when acids react with metals?

When acids react with metals, a chemical reaction takes place that produces a salt and hydrogen gas. This is a characteristic reaction of acids.

Key Points:

• Acid reacts with metal.
• Produces hydrogen gas.
• Salt is also formed.
• Common laboratory reaction.

Real-Life Example:

Zinc reacts with hydrochloric acid to release hydrogen gas.

Answer: Hydrogen

Q11. When acids react with carbonates, they produce:

Acids react with carbonates to form a salt, water, and carbon dioxide gas. The release of carbon dioxide is often observed as bubbling or effervescence.

Key Points:

• Produces carbon dioxide gas.
• Water and salt are formed.
• Characteristic carbonate reaction.
• Shows effervescence.

Real-Life Example:

Adding acid to marble chips (calcium carbonate) produces bubbles of carbon dioxide gas.

Answer: Carbon dioxide gas

Q12. A salt is formed when:

A salt is produced during a neutralization reaction in which an acid reacts with a base. Water is also formed as a by-product of the reaction.

Key Points:

• Neutralization reaction.
• Acid reacts with base.
• Produces salt and water.
• Important chemical reaction.

Real-Life Example:

Hydrochloric acid reacts with sodium hydroxide to form sodium chloride and water.

Answer: Acid reacts with base

Q13. The reaction between an acid and a base is called:

A neutralization reaction occurs when an acid reacts with a base. The acidic and basic properties cancel each other, producing salt and water.

Key Points:

• Acid-base reaction.
• Produces salt and water.
• Reduces acidity and alkalinity.
• Common in everyday life.

Real-Life Example:

Antacid tablets neutralize excess stomach acid through a neutralization reaction.

Answer: Neutralization

Q14. Which of the following is a salt?

Salts are ionic compounds formed when acids react with bases. Sodium chloride (NaCl), commonly known as table salt, is one of the most familiar salts.

Key Points:

• Formed by neutralization.
• Ionic compound.
• Contains positive and negative ions.
• Common example: NaCl.

Real-Life Example:

Table salt used in cooking is sodium chloride.

Answer: NaCl

Q15. Baking soda is chemically known as:

Baking soda is a mild alkaline substance known chemically as sodium bicarbonate (NaHCO₃). It is widely used in baking and household applications.

Key Points:

• Chemical name: Sodium bicarbonate.
• Formula: NaHCO₃.
• Used in baking.
• Mildly basic.

Real-Life Example:

Baking soda helps cakes and bread rise by releasing carbon dioxide gas when heated.

Answer: Sodium bicarbonate

Q16. Washing soda is chemically known as:

Washing soda is an important chemical compound used as a cleaning agent and water softener. Its chemical name is sodium carbonate (Na₂CO₃), and it is widely used in household and industrial cleaning applications.

Key Points:

• Chemical name: Sodium carbonate.
• Formula: Na₂CO₃.
• Used as a cleaning agent.
• Helps soften hard water.

Real-Life Example:

Washing soda is used to remove stains from clothes and improve the effectiveness of detergents.

Answer: Sodium carbonate

Q17. The taste of acids is generally:

Acids are substances that release hydrogen ions in water and are commonly recognized by their sour taste. Many naturally occurring acids in fruits contribute to their characteristic flavor.

Key Points:

• Acids taste sour.
• Release H⁺ ions in water.
• Found in many fruits.
• Examples include citric acid and acetic acid.

Real-Life Example:

Lemon and tamarind taste sour because they contain acids.

Answer: Sour

Q18. The taste of bases is generally:

Bases are substances that release hydroxide ions in water. They generally have a bitter taste and often feel slippery to the touch.

Key Points:

• Bases taste bitter.
• Release OH⁻ ions.
• Feel slippery.
• Have pH values greater than 7.

Real-Life Example:

Soap solution feels slippery because it is basic in nature.

Answer: Bitter

Q19. Which acid is present in vinegar?

Vinegar contains acetic acid, a weak organic acid responsible for its sour taste and acidic properties. Acetic acid is commonly used in cooking and food preservation.

Key Points:

• Vinegar contains acetic acid.
• Weak organic acid.
• Gives vinegar its sour taste.
• Used in food preservation.

Real-Life Example:

Vinegar is commonly added to pickles because acetic acid helps preserve food.

Answer: Acetic acid

Q20. Which acid is present in lemon?

Lemon contains citric acid, a naturally occurring organic acid found in citrus fruits. It gives lemons their characteristic sour taste and is widely used in food and beverages.

Key Points:

• Lemon contains citric acid.
• Natural organic acid.
• Gives sour taste.
• Found in citrus fruits.

Real-Life Example:

Lemon juice is often added to drinks and foods because of its refreshing sour flavor caused by citric acid.

Answer: Citric acid

Recommended Reference

Refer to NCERT textbook for detailed explanation: