Carbon and its Compounds Important Questions of Class 10 Science

1.Name the acid present in the following:
(i) Tomato
(ii) Vinegar
(iii) Tamarind

2. (a)Define olfactory indicators. Name two substances which can be used as olfactory indicator.

(b) Choose strong acids from the following: CH3COOH, H2SO4, H2CO3, HNO3

3.Explain the action of dilute hydrochloric acid on the following with chemical equation.
(i) Magnesium ribbon
(ii) Sodium hydroxide  
(iii) Crushed egg shells

4.(a) Write the chemical formula of hydrated copper sulphate and anhydrous copper sulphate.
(b) Write chemical names and formula of plaster of paris and gypsum.

5.Name the natural source of each of the following acid.
(i) Citric acid.  
(ii)Oxalic acid.   
(iii)Lactic acid.   
(iv)Tartaric acid.

6.A student detected the pH of four unknown solution A, B, C and D as follows 11,5,7 and 2. Predict the nature of the solution.

7.Equal length of magnesium ribben are taken in two test tubes 'A' and B H2SO4, is added to test tube 'A' and H2CO3 in the test tube B' in equal amounts:
(a) Identify the test tube showing vigorous reaction.
(b) Give reason to support your answer.
(c) Name the gas liberated in both the tubes. How will you prove its liberation?
(d) Write chemical equations for both reactions.
(e) Out of the two acids taken above
(i) which one will have lower pH value.
(ii) lower H plus concentration respectively.

8. How will you test for the gas which is liberated when hydrochloric acid reacts with an active metal?

9.(a) Write the name given to bases that are highly soluble in water. Give an example.
(b) How is tooth decay related to pH? How can it be prevented?
(C) Why does bee sting cause pain and irritation? Rubbing of baking soda on the sting area givesrelief. How?

10Explain why is hydrochloric acid a strong acid and acetic acid, a weak acid. How can it be verified?
(i)Explain why aqueous solution of an acid conduct electricity.
(ii) You have four solutions A B, C and D. The pH of solution A is 6, B is 9, C is 12 and D is 7,
(a) Identify the most acidic and most basic solutions.
(b) Arrange the above four solutions in the increasing order of H plus  ion concentration.
(c) State the change in colour of pH paper on dipping in solution C and D.


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