Plus One / 11th Chemistry- Book Back Answers - Unit 4 - English Medium
Tamil Nadu Board 11th Standard Chemistry - Unit 4 : Book Back Answers and Solutions
This post covers the book back answers and solutions for Unit 4 – Chemistry from the Tamil Nadu State Board 11th Standard Chemistry textbook. These detailed answers have been carefully prepared by our expert teachers at KalviTips.com.
We have explained each answer in a simple, easy-to-understand format, highlighting important points step by step under the relevant subtopics. Students are advised to read and memorize these subtopics thoroughly. Once you understand the main concepts, you’ll be able to connect other related points with real-life examples and confidently present them in your tests and exams.
By going through this material, you’ll gain a strong understanding of Chemistry Unit 4 along with the corresponding book back questions and answers (PDF format).
Question Types Covered:
- 1 Mark Questions: Choose the correct answer, Fill in the blanks, Identify the correct statement, Match the following
- 2 Mark Questions: Answer briefly
- 3, 4, and 5 Mark Questions: Answer in detail
All answers are presented in a clear and student-friendly manner, focusing on key points to help you score full marks.
All the best, Class 11 students! Prepare well and aim for top scores. Thank you!
Unit 4 :Basic Concepts of Chemistry and Chemical Calculations
I. Choose the best answer.
1. Which of the following statements about hydrogen is incorrect? (NEET - 2016)
a) Hydrogen ion,H3O+exists freely in solution.
b) Dihydrogen acts as a reducing agent.
c) Hydrogen has three isotopes of which tritium is the most common.
d) Hydrogen never acts as cation in ionic salts.
Answer Key:
c) Hydrogen has three isotopes of which tritium is the most common.
2. Water gas is
c) CO + H2
3. Which one of the following statements is incorrect with regard to ortho and para dihydrogen?
a) They are nuclear spin isomers
b) Ortho isomer has zero nuclear spin whereas the para isomer has one nuclear spin
c) The para isomer is favoured at low temperatures
d) The thermal conductivity of the para isomer is 50% greater than that of the ortho isomer.
Answer Key:
b) Ortho isomer has zero nuclear spin whereas the para isomer has one nuclear spin
4.Ionic hydrides are formed by
a) halogens
b) chalcogens
c) inert gases
d) group one elements.
Answer Key:
d) group one elements.
5. Tritium nucleus contains
a) 1p + 0n
b) 2 p + In
c) 1p + 2n
d) none of these
Answer Key:
c) 1p + 2n
6. Non-stoichiometric hydrides are formed by
a) palladium, vanadium
b) carbon, nickel
c) manganese, lithium
d) nitrogen, chlorine
Answer Key:
a) palladium, vanadium
7. Assertion: Permanent hardness of water is removed by treatment with washing soda.
Reason: Washing soda reacts with soluble calcium and magnesium chlorides and sulphates in hard water to form insoluble carbonates
a) Both assertion and reason are true and reason is the correct explanation of assertion.
b) Both assertion and reason are true but reason is not the correct explanation of assertion.
c) Assertion is true but reason is false
d) Both assertion and reason are false
Answer Key:
a) Both assertion and reason are true and reason is the correct explanation of assertion.
8. If a body of a fish contains 1.2 g hydrogen in its total body mass, if all the hydrogen is replaced with deuterium then the increase in body weight of the fish will be
a) 1.2 g
b) 2.4 g
c) 3.6 g
d)
Answer Key:
a) 1.2 g
9. The hardness of water can be determined by volumetrically using the reagent
a) sodium thio sulphate
b) potassium permanganate
c) hydrogen peroxide
d) EDTA
Answer Key:
d) EDTA
10. The cause of permanent hardness of water is due to
c) CaCl2
11. Zeolite used to soften hardness of water is, hydrated
a) Sodium aluminium silicate
b) Calcium aluminium silicate
c) Zinc aluminium borate
d) Lithium aluminium hydride
Answer Key:
a) Sodium aluminium silicate
12. A commercial sample of hydrogen peroxide marked as 100 volume H₂O₂, it means that
13. When hydrogen peroxide is shaken with an acidified solution of potassium dichromate in presence of ether, the ethereal layer turns blue due to the formation of
a) Hydrogen ion,H3O+exists freely in solution.
b) Dihydrogen acts as a reducing agent.
c) Hydrogen has three isotopes of which tritium is the most common.
d) Hydrogen never acts as cation in ionic salts.
Answer Key:
c) Hydrogen has three isotopes of which tritium is the most common.
2. Water gas is
a) H2O(g)
b) CO
+ H2O
c) CO
+ H2
d) CO
+ N2
Answer Key:c) CO + H2
3. Which one of the following statements is incorrect with regard to ortho and para dihydrogen?
a) They are nuclear spin isomers
b) Ortho isomer has zero nuclear spin whereas the para isomer has one nuclear spin
c) The para isomer is favoured at low temperatures
d) The thermal conductivity of the para isomer is 50% greater than that of the ortho isomer.
Answer Key:
b) Ortho isomer has zero nuclear spin whereas the para isomer has one nuclear spin
4.Ionic hydrides are formed by
a) halogens
b) chalcogens
c) inert gases
d) group one elements.
Answer Key:
d) group one elements.
5. Tritium nucleus contains
a) 1p + 0n
b) 2 p + In
c) 1p + 2n
d) none of these
Answer Key:
c) 1p + 2n
6. Non-stoichiometric hydrides are formed by
a) palladium, vanadium
b) carbon, nickel
c) manganese, lithium
d) nitrogen, chlorine
Answer Key:
a) palladium, vanadium
7. Assertion: Permanent hardness of water is removed by treatment with washing soda.
Reason: Washing soda reacts with soluble calcium and magnesium chlorides and sulphates in hard water to form insoluble carbonates
a) Both assertion and reason are true and reason is the correct explanation of assertion.
b) Both assertion and reason are true but reason is not the correct explanation of assertion.
c) Assertion is true but reason is false
d) Both assertion and reason are false
Answer Key:
a) Both assertion and reason are true and reason is the correct explanation of assertion.
8. If a body of a fish contains 1.2 g hydrogen in its total body mass, if all the hydrogen is replaced with deuterium then the increase in body weight of the fish will be
a) 1.2 g
b) 2.4 g
c) 3.6 g
d)
Answer Key:
a) 1.2 g
9. The hardness of water can be determined by volumetrically using the reagent
a) sodium thio sulphate
b) potassium permanganate
c) hydrogen peroxide
d) EDTA
Answer Key:
d) EDTA
10. The cause of permanent hardness of water is due to
a)
Ca(HCO3)2
b)
Mg(HCO3)2
c)
CaCl2
d)
MgCO3
Answer Key:c) CaCl2
11. Zeolite used to soften hardness of water is, hydrated
a) Sodium aluminium silicate
b) Calcium aluminium silicate
c) Zinc aluminium borate
d) Lithium aluminium hydride
Answer Key:
a) Sodium aluminium silicate
12. A commercial sample of hydrogen peroxide marked as 100 volume H₂O₂, it means that
a) 1
ml of H₂O2, will give 100 ml O2, at STP
b) 1 L
of H₂O2, will give 100 ml O2, at STP
c) 1 L
of H₂O2, will give 22.4 L O2,
d) 1
ml of H₂O2, will give 1 mole of O2, at STP
Answer Key:a) 1
ml of H₂O2, will give 100 ml O2, at STP
13. When hydrogen peroxide is shaken with an acidified solution of potassium dichromate in presence of ether, the ethereal layer turns blue due to the formation of
a) Cr2O3
b) CrO42-
c)
CrO(O₂)2,
d)
none of these
Answer
Key:
c)
CrO(O₂)2,
14.
For decolourisation of 1 mole of acidified KMnO4, the moles of H2O2
required is
a) 1/2
b) 3/2
c) 5/2
d) 7/2
Answer Key:
c) 5/2
b) 3/2
c) 5/2
d) 7/2
Answer Key:
c) 5/2
15.
Volume strength of 1.5 NH2O2 is
a) 1.5
b) 4.5
c) 16.8
d) 8.4
Answer Key:
d) 8.4
b) 4.5
c) 16.8
d) 8.4
Answer Key:
d) 8.4
16.
The hybridisation of oxygen atom is H2O and H2O2 are, respectively
a) sp
and sp3
b) sp
and sp
c) sp
and sp2
d) sp3
and sp³
Answer
Key:
d) sp3
and sp³
17.
The reaction H3PO2 + D2O →H2DP2 + HDO indicates that
hypo-phosphorus acid is
a) tribasic acid
b) dibasic acid
c) mono basic acid
d) none of these
Answer Key:
c) mono basic acid
18. In solid ice, oxygen atom is surrounded
a) tetrahedrally by 4 hydrogen atoms
b) octahedrally by 2 oxygen and 4 hydrogen atoms
c) tetrahedrally by 2 hydrogen and 2 oxygen atoms
d) octahedrally by 6 hydrogen atoms
Answer Key:
a) tetrahedrally by 4 hydrogen atoms
19. The type of H-bonding present in ortho nitro phenol and p-nitro phenol are respectively
a) inter molecular H-bonding and intra molecular H-bonding
b) intra molecular H-bonding and inter molecular H-bonding
c) intra molecular H - bonding and no H - bonding
d) intra molecular H - bonding and intra molecular H - bonding
Answer Key:
b) intra molecular H-bonding and inter molecular H-bonding
20. Heavy water is used as
a) moderator in nuclear reactions
b) coolant in nuclear reactions
c) both (a) and (b)
d) none of these
Answer Key:
c) both (a) and (b)
21. Water is a
a) basic oxide
b) acidic oxide
c) amphoteric oxide
d) none of these
Answer Key:
c) amphoteric oxide
c) mono basic acid
d) none of these
Answer Key:
c) mono basic acid
18. In solid ice, oxygen atom is surrounded
a) tetrahedrally by 4 hydrogen atoms
b) octahedrally by 2 oxygen and 4 hydrogen atoms
c) tetrahedrally by 2 hydrogen and 2 oxygen atoms
d) octahedrally by 6 hydrogen atoms
Answer Key:
a) tetrahedrally by 4 hydrogen atoms
19. The type of H-bonding present in ortho nitro phenol and p-nitro phenol are respectively
a) inter molecular H-bonding and intra molecular H-bonding
b) intra molecular H-bonding and inter molecular H-bonding
c) intra molecular H - bonding and no H - bonding
d) intra molecular H - bonding and intra molecular H - bonding
Answer Key:
b) intra molecular H-bonding and inter molecular H-bonding
20. Heavy water is used as
a) moderator in nuclear reactions
b) coolant in nuclear reactions
c) both (a) and (b)
d) none of these
Answer Key:
c) both (a) and (b)
21. Water is a
a) basic oxide
b) acidic oxide
c) amphoteric oxide
d) none of these
Answer Key:
c) amphoteric oxide
II. Short Answer Questions
11th ChemistryIII. Long Answer Questions
11th ChemistryIV. Exercise
11th Chemistry
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