Science Recaptulation Question Bank


Class 7 Acids,bases and salts


Question Bank for Recaptulation

1.Which one is an organic acid?

(a)    Sulphuric acid (b) Hydrochloric acid (c) Nitric acid (d) Lactic acid

2.    Acid turns blue litmus

(a)    Red (b) Orange (c) Pink (d) Green

3.    Which ofthe following is a strong acid?

(a)    Citric acid (b) Acetic acid (c) Malic acid (d) Sulphuric acid

4.    Which gas is released when acid reacts with metals?

(a)    Hydrogen (b) Oxygen (c) Nitrogen (d) Carbon dioxide

5.    Match the following

   

Column A    Column B

a. Hydrochloric acid    i. Natural indicator

b. Carbonic acid    ii. Turns red in acid

c. Sodium hydroxide        iii. Strong acid

d. Turmeric    iV. Organic acid

e. Blue litmus    v. Strong base

6.    Fill in the blanks

(a)    When acid and base react together a new compound called    is formed.

(b)    All acids contain

(c)    Metal on heating or burning produce    of metals.

(d)    Turmericis a    indicator.

(e)    Minerals acids are obtained from

 

7.    What are indicators? Give two examples.

8.    What is neutralization reaction?

9.    What are alkalies? Give two examples.

10.    Classify the following as organic and mineral acids?

Hydrochloric acid, Citric acid, Malic acid, Nitric acid, Oxalic acid, Sulphuric acid.



Class — Vil Science (Acids, Bases and Salts)

Answer key

1.  

2. a 3.  

4.    a

5.    (a) — (iii), (b) — (iv), (c) — (v), (d) — (i), (e) — (ii).

6.    (a) Salt (b) hydrogen (c) oxide (d) natural (e) minerals. 

7.    Indicators are substances that are used to test whether a substance is acidic or basic or neutral in nature. They change their colour when added to a solution containing an acidic or a basic substance. Indicators are of two types - natural and artificial.

Natural Indicator: Turmeric , Litmus

Artificial Indicators: Phenolphthalein

8.    The reaction between an acid and a base two form -salt and water is called neutralization reaction.

NaOH + HCI-> NaC1 + H20.  

9.    Metal oxides are basic in nature. Those bases that dissolve in water are called alkalies. Sodium hydroxide and Potassium hydroxide are two common example of alkalies.

10.

Organic acids      Mineral acids

Citric acid    Hydrochloric acid

Malic acid    Nitric acid

Oxalic acid.    Hydrochloric acid

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