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A student Prepared 20% sodium hydroxide solution in a beaker to study saponification reaction. Some observations related to this are given below :

(I) Sodium hydroxide solution turns red litmus blue

(II) Sodium hydroxide readily dissolves in water

(III) The beaker containing solution appears cold when touched from outside

(IV) The blue litmus paper turns red when dipped into the solution

The correct observations are :

I, II and IV

I, II and III

Only III and IV

Only I and II

Solution

D.

Only I and II

The correct option is D.

Sodium hydroxide being a base dissolves in water to form an alkaline solution which turns red litmus blue. A large amount of heat is dissipated, when sodium hydroxide is dissolved in water because the process is exothermic in nature. So, when touched from outside the beaker containing sodium hydroxide solution should be hot.

Some More Questions From Control and Coordination Chapter

What are non-metallic oxides? Substantiate your answer.

Take 5 ml hydrochloric acid in a boiling tube or a conical flask. Add a few pieces of zinc granules to it.

(a) What do you observe on the surface of zinc granules?
(b) Name the gas evolved.
(c) What happens when the above gas is passed through soap solution?
(d) What happens when a burning candle is brought near the gas filled tube?

Name four acids and bases. Write their formulae.

Name the various kind of oxides and mention their properties.

What are acids? How are they produced?

Mention important characteristics of acids.

Why the vessels of copper and brass need ‘Kalai’?

How can you test the presence of an acid in any substance?

Why are acids not stored in metal containers? Containers/vessels made from which material are safe to store acids.

A solution turns red litmus paper blue. What does this indicate about the chemical nature of the solution?

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