Page 48 - Science Class 07

3. Which of the following is not a base?
(a) Sodium hydroxide (b) Magnesium hydroxide

(c) Copper carbonate (d) Ammonium hydroxide
4. Which of the following is not a weak acid?
(a) Tartaric acid (b) Nitric acid

(c) Ace c acid (d) Oxalic acid
5. Which of the following is not a property of acid?
(a) Sour taste (b) Turns blue litmus red
(c) Turns methyl orange solu on orange (d) Slippery in nature

6. Which of the following is not a weak base?
(a) NH OH (b) NaOH
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(c) Mg(OH) (d) Ca(OH) 2
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B. Fill in the blanks.
1. It is common to see substances change states from one state of ____________ to another.
2. All the naturally occurring acids are weak because of their ____________ nature.
3. The most commonly used indicators are litmus paper, methyl orange and ____________ .

4. ____________ , which is a commonly used spice, is used as indicator.
5. ____________ can be prepared by dissolving metal oxides in water.
C. Write the effects of acid and base on the following indicators.

Indicator Acid Base
1. Blue/Red litmus
2. Methyl orange

3. Phenolphthalein
D. Very short answer ques ons.

1. How can you classify different substances on the basis of their chemical proper es?
2. Why lemon is called citrus fruit?
3. Name any three weak acids.
4. What are called organic acids?
5. Name the sources of organic acids.

6. Name any three inorganic acids.
7. What do you mean by indicators?
8. What are basic substances?

9. What do you mean by alkalis?
10. What is neutraliza on?
E. Short answer ques ons.
1. Differen ate between acids and bases.

2. How acids are formed?

48 Science-7