Chemistry Questions and Answers – s-Block Elements – Important Compounds of Sodium


This set of Chemistry Objective Questions and Answers for Class 11 focuses on “s-Block Elements – Important Compounds of Sodium”.

1. Which of the following compound is formed when caustic soda is reacted with ferric chloride?
a) potassium chloride
b) sodium chloride only
c) ferric hydroxide only
d) both ferric hydroxide and sodium chloride
View Answer

Answer: d
Explanation: When 1 mole of ferric chloride is reacted with 3 moles of caustic soda, 1 mole of ferric hydroxide which is insoluble and three moles of sodium chloride are formed. It is an example of how caustic soda reacts with salt.

2. Caustic soda and quicklime are together known as ___________
a) washing soda
b) caustic soda
c) soda lime
d) quicklime
View Answer

Answer: c
Explanation: A mixture of caustic soda and quicklime is known as soda lime, where caustic soda as nothing but sodium hydroxide and quicklime is calcium oxide. They are represented by the chemical formula NaOH and CaO respectively.

3. Which of the following is a correct formula for washing soda?
a) Na2CO3.10H2O
b) Na2CO3
c) NaCO3
d) Na2CO
View Answer

Answer: a
Explanation: Washing soda is nothing but sodium carbonate it contains two atoms of sodium, one atom of carbon, three atoms of Oxygen and 10 moles of water in one molecule its chemical formula is given by Na2CO3.10H2O.

4. Which of the following as a Process to prepare washing soda?
a) Solvay process
b) Amalgam process
c) Boiling
d) Clark’s process
View Answer

Answer: a
Explanation: In Solvay process, carbon dioxide gas is passed through brine solution saturated with Ammonia, which results in the formation of sodium bicarbonate, which is filtered and dried it is ignited to give sodium carbonate.

5. Soda Ash is a ___________ salt.
a) moist
b) anhydrous
c) electrolysis
d) wet
View Answer

Answer: b
Explanation: Sodium carbonate crystallizes from water as decahydrate which effloresces. It on exposure to dry air forms monohydrate which on heating changes to the anhydrous side that is Soda Ash. Therefore, it is an anhydrous salt.
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6. Sodium carbonate forms and ___________ solution.
a) neutral
b) ascetic
c) acidic
d) alkaline
View Answer

Answer: d
Explanation: Sodium carbonate on hydrolysis forms an alkaline solution, when sodium carbonate reacts with water it forms carbonic acid which is a weak acid and sodium hydroxide which is a strong base, therefore forming an alkaline solution.

7. Which of the following is not a use of sodium carbonate?
a) electronics
b) laundering
c) cleaning
d) textile industry
View Answer

Answer: a
Explanation: Sodium carbonate or washing soda, which is represented by the chemical formula Na2CO3.10H2O, is used in water softening, laundering, cleaning, paper, Paints and textile industries, it is not used in electronics.

8. Sodium bicarbonate is also known as ___________
a) brine solution
b) washing soda
c) baking soda
d) caustic soda
View Answer

Answer: c
Explanation: Sodium Bicarbonate is also known as baking soda, sodium carbonate is also known as washing soda, Sodium Hydroxide is also known as caustic soda and 28% of NaCl solution is known as a brine solution.

9. Sodium bicarbonate on heating does not give ___________
a) nitrogen
b) water
c) sodium carbonate
d) carbon dioxide
View Answer

Answer: a
Explanation: In the presence of the heat 2 moles of sodium bicarbonate gives 1 mole of sodium carbonate along with one mole of carbon dioxide and one mole of water in an aqueous medium. Sodium bicarbonate is alkaline due to anionic hydrolysis.

10. Is baking soda useful?
a) yes
b) no
c) may be
d) may not be
View Answer

Answer: a
Explanation: Yes, baking soda as used as a constituent of baking powder which is a mixture of sodium Bicarbonate, starch and potassium bitartrate or cream of tartar rate and in medicine to remove the acidity of the stomach, a mild antiseptic for skin infections and also in the fire extinguisher.

11. Sodium chloride has a ___________ nature.
a) alkaline
b) deliquescent
c) acidic
d) basic
View Answer

Answer: b
Explanation: Delinquency is a tendency to dissolve. Sodium chloride is obtained by evaporation of seawater but due to the presence of impurities like calcium chloride and magnesium chloride, it has deliquescent nature.

12. Pure NaCl is gets precipitated due to the ___________
a) common electron effect
b) common Ion effect
c) common cation effect
d) common Proton effect
View Answer

Answer: b
Explanation: The sodium chloride that’s obtained by seawater evaporation, is purified by passing through HCl gas through the impure saturated solution of NaCl and due to common Ion effect, pure NaCl gets precipitated 28% of NaCl solution is called Brine.

13. Which of the following is a method of preparation of sodium hydroxide?
a) syngas reaction
b) causticizing process
c) purification
d) water gas reaction
View Answer

Answer: b
Explanation: A 10 percent solution of sodium carbonate is treated with milk of lime, this is known as causticizing process and is one of the methods of preparation of sodium hydroxide, sodium carbonate reacts with calcium hydroxide to form calcium carbonate as precipitate and sodium hydroxide.

14. What happens when sodium amalgam is treated with water?
a) Sodium sulfate is formed
b) Sodium carbonate is formed
c) Sodium Hydroxide is formed
d) Sodium bicarbonate is formed
View Answer

Answer: c
Explanation: In the electrolytic process, which involves Nelson cell and castner kellner cell, the sodium amalgam is treated with water to give sodium hydroxide, hydrogen gas, and mercury. Sodium amalgam is formed when sodium metal discharges at the mercury cathode combining with mercury.

15. Sodium Hydroxide is not soluble in water.
a) true
b) false
View Answer

Answer: b
Explanation: The physical properties of sodium hydroxide are that it is white translucent solid, readily soluble and water as the crystals of sodium hydroxide a deliquescent in nature. It is also known as caustic soda.

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