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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
Write the chemical name and formula of caustic soda.
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:
hydrogen formed?
Answer the following question:
List the important products of the Chlor-alkali process. Write one important use of each.
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?
While electrolysing water before passing the current some drops of an acid are added. Why? Name the gases liberated at cathode and anode. Write the relationship between the volume of gas collected at anode and the volume of gas collected at cathode.
Chlorine gas was prepared using electrolysis of brine solution. Write the chemical equation to represent the change. Identify the other products formed in the process and give one application of each.
