CLASS 7 ACIDS BASES AND SALTS REVISION

CLASS 7               ACIDS BASES AND SALTS

REVISION

I. Fill in the blanks:-

1. An acid is ____________ by a base .

2. Phenolphthalein is an __________ indicator.

II. Choose the correct option:-

1. A Soap Solution is –

a) Basic b) Acidic c) Alkaline d) Neutral

2. CO2 + H2O →

a) Sulphuric acid b)Nitric acid c) Carbonic acid d) None

III. Name the following:-

1. Soluble bases.

2. A Chemical used as a food preservative.

IV Define the following:-

 1. Neutralisation Reaction 2. Acid-Base Indicator

V Give Reasons:-

1. Sour things are not kept in metal pots

2.  Acids are sour in taste.

VI. Answer in 20 words :-

1 Name three mineral acids and give their formulae?

2 What is acid and base?

VIII Answer in 40 words:-

1. What are general properties of bases?

2. What are general properties of acids?

3. Name an acidic gas which is discharged into the atmosphere on the burning of fuels like coal

& natural gas. How is this gas formed.

IX Write one use of the following:-

1. Sulphuric acid.

2. Citric acid

3. Sodium Carbonate

4. Potassium Nitrate

5. Calcium phosphate

X.While playing in a park, a child was stung by a wasp. Some

elders suggested applying paste of baking soda and others

lemon juice as remedy. Which remedy do you think is

appropriate and why?

XI. Form a sentence using the following words – baking soda, ant

bite, moist, effect, neutralised, rubbing.

Fill the blanks in the following sentences

(a) Lemon juice and vinegar taste ___________ because they

contain ___________.

(b) Turmeric and litmus are _________ acid-base indicators.

(c) Phenolphthalein gives _________ colour with lime water.

(d) When an acidic solution is mixed with a basic solution,

they _________ each other forming _________ and water.

XII.You are provided with three test tubes A, B and C as shown in

 with different liquids. What will you observe when

you put

(a) a piece of blue litmus paper in each test tube.

(b) a piece of red litmus paper in each test tube.

(c) a few drops of phenolphthalein solution to each test tube.

Test tube A contain solution of tartaric acid.

Test tube B contain soap solution .

Test tube C contain pure water.