Advertisements
Advertisements
प्रश्न
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 :-
(A) I, II and IV
(B) I, II and III
(C) only III and IV
(D) only I and II
उत्तर
Sodium hydroxide is a base. It readily dissolves in water to form an alkaline solution, which turns red litmus paper blue. When sodium hydroxide is dissolved in water, a large amount of heat is evolved, as the process is exothermic in nature. Thus, the beaker containing the sodium hydroxide solution should feel hot when touched from the outside.
Hence, the correct option is D.
APPEARS IN
संबंधित प्रश्न
We need 20% aqueous solution of sodium hydroxide for the study of saponification reaction. When we open the lid of the bottle containing solid sodium hydroxide we observe it in which form?
(A) Colourless transparent beads
(B) Small white beads
(C) White pellets/flakes
(D) Fine white powder
The electrolysis of an aqueous solution of sodium chloride gives us three products. Name them.
During the electrolysis of a saturated solution of sodium chloride, where is:
chlorine formed?
During the electrolysis of a saturated solution of sodium chloride, where is:
sodium hydroxide formed?
A student prepared 20% sodium hydroxide solution in a beaker containing water. The observations noted by him are given below.
I. Sodium hydroxide is in the form of pellets.
II. It dissolves in water readily.
III. The beaker appears cold when touched from outside.
IV. The red litmus paper turns blue when dipped into the solution.
The correct observations are:
(A) I, II, and III
(B) II, III and IV
(C) III, IV and I
(D) I, II and IV
An aqueous solution turns red litmus solution blue. Excess addition of which of the following solution would reverse the change?
Sodium hydroxide is used ____________.
Sodium hydroxide turns phenolphthalein solution.
The Salt Story
From: The New Indian Express 9 March 2021
The salt pans in Marakkanam, a port town about 120 km from Chennai are the third largest producer of salt in Tamil Nadu. Separation of salt from water is a laborious process and the salt obtained is used as raw materials for manufacture of various sodium compounds.
One such compound is Sodium hydrogen carbonate, used in baking, as an antacid and in soda acid fire extinguishers.
The table shows the mass of various compounds obtained when 1litre of sea water is evaporated.
| COMPOUND | FORMULA | MASS OF SOLID PRESENT /g |
| Sodium Chloride | NaCl | 28.0 |
| Magnesium Chloride | MgCl2 | 8.0 |
| Magnesium Sulphate | MgSO4 | 6.0 |
| Calcium Sulphate | CaSO4 | 2.0 |
| Calcium Carbonate | CaCO3 | 1.0 |
| TOTAL AMOUNT OF SALT OBTAINED | 45.0 | |
What is the saturated solution of Sodium Chloride called?
Sodium hydroxide is termed an alkali while Ferric hydroxide is not because ______.
