Exploring Substances Acidic, Basic, and Neutral

What is the main message of the chapter "Exploring Substances: Acidic, Basic, and Neutral"?

1. All substances have the same chemical properties.
2. Acids, bases, and neutral substances have different properties, can be identified using indicators, and have many practical uses in daily life.
3. Indicators are unnecessary in science.
4. Acids and bases are useful only in laboratories.

Which property helps identify an acid?

1. Bitter taste
2. Slippery feel
3. Sour taste and blue litmus turning red
4. Turning red litmus blue

Why should concentrated acids and bases be handled carefully?

1. They are edible.
2. They can cause burns and damage skin.
3. They are completely harmless.
4. They change into water automatically.

Which of the following substances is acidic?

1. Baking soda solution
2. Soap solution
3. Lemon juice
4. Lime water

Which natural indicator changes colour in acidic and basic solutions?

1. Turmeric
2. Chalk
3. Sugar
4. Salt

Which of the following is commonly used as an antacid?

1. Lemon juice
2. Vinegar
3. Milk of magnesia
4. Orange juice

What happens during a neutralisation reaction?

1. Two acids react together.
2. An acid reacts with a base to form salt and water.
3. A base reacts with another base.
4. Water changes into acid.

What is the main property of bases?

1. They taste sour.
2. They turn blue litmus red.
3. They turn red litmus blue.
4. They are always colourless.

Which of the following substances contains acetic acid?

1. Milk
2. Vinegar
3. Soap
4. Baking soda

Which colour change occurs when red litmus paper is placed in a basic solution?

1. Red to blue
2. Blue to red
3. Red to yellow
4. No change

Which of the following is a natural acid?

1. Lemon juice
2. Soap solution
3. Baking soda
4. Washing powder

Which indicator is commonly used to test acids and bases?

1. Sugar
2. Salt
3. Litmus paper
4. Sand

Which substance is considered neutral?

1. Vinegar
2. Lemon juice
3. Pure water
4. Soap solution

Which of the following is a basic substance?

1. Lemon juice
2. Vinegar
3. Soap solution
4. Orange juice

What is an acidic substance?

1. A substance that tastes bitter and feels slippery
2. A substance that turns blue litmus paper red
3. A substance that turns red litmus paper blue
4. A substance that has no effect on litmus paper