Class 7 Acids Bases and Salts

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Multiple Choice Questions (MCQs)

  1. A neutralisation reaction between a strong acid and weak base forms :

(a) an acidic salt

(b) a basic salt

(c) a neutral salt

(d) a salt

  1. Which of the following is a property of an acid?

(a) Sour taste

(b) Sweet taste

(c) Bitter taste

(d) Salty taste

  1. Manure is added when the soil is too

(a) acidic

(b) basic

(c) neutral

(d) none of these

  1. Which of the following is a strong acid?

(a) Nitric acid

(b) Citric acid

(c) Acetic acid

(d) Tartaric acid

  1. The acid produced naturally in our stomach is :

(a) tartaric acid

(b) citric acid

(c) hydrochloric acid

(d) sulphuric acid

  1. Which of the following is a strong base?

(a) Calcium hydroxide

(b) Sodium hydroxide

(c) Sodium carbonate

(d) Ammonium hydroxide

  1. With which of the following ‘Milk of Magnesia’ be reacted so as to have neutralisation reaction?

(a) Baking soda

(b) Vinegar

(c) Ammonia solution

(d) Quicklime

 Ans.

  1. (d) a salt
  2. (a) Sour taste
  3. (b) basic
  4. (a) Nitric acid
  5. (c) Hydrochloric acid
  6. (b) Sodium hydroxide
  7. (b) Vinegar

Fill in the blanks with suitable words

  1. The reaction between an acid and a base is called———- ———–.

2.——————– is used to tell whether a material is acidic or basic.

  1. Bases turn purple cabbage juice to—————-
  1. Acid turns—– ——– litmus to ——-—- —–
  1. Acid + Base +————- —————-+ water.

6. Hydrochloric acid + Sodium hydroxide—–—- + water.

Ans.

  1. neutralization reaction
  2. Litmus paper
  3. green
  4. Blue, Red 
  5. salt
  6. salt

Very Short Answer Type Questions.

  1. Write the name of one natural indicator and one synthetic indicator.

Ans. Turmeric is naturally occurring indicator. Methyl orange is a synthetic indicator.

  1. What is the name of the acid-base indicator which is extracted from lichens?

Ans. The solution is obtained from lichens. Litmus solution is used to detect the acidic and basic characteristic of a substance.

  1. What colour do the following indicators turn when added to a base?

(a) Litmus solution

(b) China rose indicator

(c) Turmeric paper

(d) Phenolphthalein

Ans. (a) Litmus solution when litmus solution is added to a basic solution, it turns blue.

(b) China rose indicator solution turns from light pink to green.

(c) Turmeric paper bases turn the yellow turmeric paper to read.

(d) Phenolphthalein indicator gives pink colour in basic solution.

  1. Name one indicator which turns red on adding a base?

Ans. Turmeric paper bases turn the yellow turmeric paper to read.

  1. Name two strong acids and two strong bases.

Ans. Two strong acids are:

Acetic Acid

Formic Acid

Two strong bases are:

Sodium hydroxide

Potassium hydroxide

  1. Which chemical is injected by an ant, when it stings to one’s hand?

Ans. Formic acid is present in ant’s sting.

7. Which chemical is known as the king of acids?

Ans. Sulphuric acid is called the king of chemicals because it has a large number of applications.

  1. Give one characteristic property of acids.

Ans. Acids have a sour taste.

  1. Write one characteristic property of bases

Ans. Bases have a bitter taste.


 

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 Summative Assessment – II