Plus One / 11th Chemistry- Book Back Answers - Unit 5 - English Medium
Tamil Nadu Board 11th Standard Chemistry - Unit 5 : Book Back Answers and Solutions
This post covers the book back answers and solutions for Unit 5 – 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 5 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 5 :Alkali and Alkaline Earth Metals
I. Choose the best answer.
1. For
alkali metals, which one of the following trends is incorrect?
a)
Hydration energy: Li > Na > K > Rb
b)
lonisation energy: Li > Na > K > Rb
c) Density:
Li < Na < K < Rb
d)
Atomic size: Li < Na < K < Rb
Answer
Key:
c) Density:
Li < Na < K < Rb
2.
Which of the following statements is incorrect?
a) Li+
has minimum degree of hydration among alkali metal cations.
b) The
oxidation state of K in KO2 is
+ 1
c)
Sodium is used to make Na / Pb alloy
d)
MgSO4, is readily soluble in water
Answer
Key:
a) Li+
has minimum degree of hydration among alkali metal cations.
3.
Which of the following compounds will not evolve H2 gas on reaction
with alkali metals?
a)
ethanoic acid
b)
ethanol
c)
phenol
d)
none of these
Answer
Key:
d)
none of these
4. Which
of the following has the highest tendency to give the reaction M +(g) M +(aq)
a) Na
b) Li
c) Rb
d) K
Answer
Key:
b) Li
5.
sodium is stored in.
a)
alcohol
b)
water
c)
kerosene
d)
none of these
Answer
Key:
c)
kerosene
6. RbO2,
is
a)
superoxide and paramagnetic
b)
peroxide and diamagnetic
c)
superoxide and diamagnetic
d)
peroxide and paramagnetic
Answer
Key:
a)
superoxide and paramagnetic
7.
Find the wrong statement
a)
sodium metal is used in organic qualitative analysis
b)
sodium carbonate is soluble in water and it is used in inorganic qualitative
analysis
c)
potassium carbonate can be prepared by solvay process
d)
potassium bicarbonate is acidic salt
Answer
Key:
c)
potassium carbonate can be prepared by solvay process
8.
Lithium shows diagonal relationship with
a)
sodium
b)
magnesium
c)
calcium
d)
aluminium
Answer
Key:
b)
magnesium
9.
Incase of alkali metal halides, the ionic character increases in the order
a) MF
< MCl < MBr < MI
b) MI
< MBr < MCl < MF
c) MI
< MBr < MF < MCl
d)
none of these
Answer
Key:
b) MI
< MBr < MCl < MF
10. In
which process, fused sodium hydroxide is electrolysed for extraction of sodium
?
a)
Castner's process
b)
Cyanide process
c)
Down process
d) All
of these
Answer
Key:
a)
Castner's process
11.
The product obtained as a result of a reaction of nitrogen with CaC2,
is (NEET -Phase I)
a) Ca
(CN)3
b)
CaN,
c) Ca
(CN)2
d) Ca3(CN)2
Answer
Key:
c) Ca
(CN)2
12.
Which of the following has highest hydration energy
a)
MgCl2,
b) Ca Cl2,
c) Ba Cl2,
d) Sr Cl2,
Answer
Key:
a)
MgCl2,
13.
Match the flame colours of the alkali and alkaline earth metal salts in the
bunsen burner
(p)
Sodium (1) Brick
red
(q)
Calcium (2)
Yellow
(r)
Barium (3)
Lilac (violet)
(s)
Strontium (4) Apple
green
(t)
Cesium (5)
Crimson red
(u)
Potassium (6) Blue
a) p –
2, q – 1, r – 4, s – 5, t – 6, u –3
b) p –
1, q – 2, r – 4,
s – 5, t – 6, u – 3
c) p –
4, q – 1, r – 2, s – 3, t – 5, u – 6
d) p –
6, q –5, r
–4 s – 3, t – 1, u – 2
Answer
Key:
a) p –
2, q – 1, r – 4, s – 5, t – 6, u –3
14.
Assertion : Generally alkali and alkaline earth metals form superoxides
Reason
: There is a single bond between O and O in superoxides.
a) both
assertion and reason are true and reason is the correct explanation of
asser-tion
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:
d)
both assertion and reason are false
15.
Assertion : BeSO4, is soluble in water while BaSO4, is
not
Reason
: Hydration energy decreases down the group from Be to Ba and lattice energy
remains almost constant.
a)
both assertion and reason are true and reason is the correct explanation of
asser-tion
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
asser-tion
16.
Which is the correct sequence of solubility of carbonates of alkaline earth
metals ?
a)
BaCO3, > SrCO3, > CaCO3, > MgCO3,
b)
MgCO3, > CaCO3, > SrCO3, > BaCO3,
c)
CaCO3, > BaCO3 > SrCO3, > MgCO3,
d)
BaCO3, > CaCO3, > SrCO3, > MgCO3,
Answer
Key:
b)
MgCO3, > CaCO3, > SrCO3, > BaCO3,
17. In
context with beryllium, which one of the following statements is incorrect? (NEET
Phase 2)
a) It
is rendered passive by nitric acid
b) It
forms Be2C
c) Its
salts are rarely hydrolysed
d) Its
hydride is electron deficient and polymeric
Answer
Key:
c) Its
salts are rarely hydrolysed
18.
The suspension of slaked lime in water is known as (NEET Phase - II)
a)
lime water
b)
quick lime
c)
milk of lime
d)
aqueous solution of slaked lime
Answer
Key:
c)
milk of lime
19. A
colourless solid substance (A) on heating evolved CO2, and also gave
a white resi-due, soluble in water. Residue also gave CO2, when treated with
dilute HCl,
a) Na2,
CO3,
b)
NaHCO3,
c)
CaCO3,
d)
Ca(HCO3)2,
Answer
Key:
b)
NaHCO3,
20.
The compound (X) on heating gives a colourless gas and a residue that is
dissolved in water to obtain (B). Excess of CO2, is bubbled through
aqueous solution of B, C is formed. Solid (C) on heating gives back X. (B) is
a)
CaCO3,
b)
Ca(OH)2,
c) Na2,
CO3,
d)
NaHCO3,
Answer
Key:
b)
Ca(OH)2,
21.
Which of the following statement is false? (NEET - Phase 1)
a) Ca³+
ions are not important in maintaining the regular beating of the heart
b) Mg2+
ions are important in the green parts of the plants
c) Mg2+
ions form a complex with ATP
d) Ca
ions are important in blood clotting
Answer
Key:
a) Ca³+
ions are not important in maintaining the regular beating of the heart
22.
The name 'Blue John' is given to which of the following compounds?
a) CaH2,
b) CaF2,
c) Ca3(PO4)
2
d) CaO
Answer
Key:
b) CaF2,
23.
Formula of Gypsum is
a)
CaSO4. 2H2O
b)
CaSO .½ H2O
c) 3
CaSO4. H2O
d) 2
CaSO.2H2O
Answer
Key:
a)
CaSO4. 2H2O
24.
When CaC2, is heated in atmospheric nitrogen in an electric furnace
the compound formed is
a) Ca(CN)2
b)
CaNCN
c) CaC2N2,
d)
CaNC2,
Answer
Key:
b)
CaNCN
25.
Among the following the least thermally stable is
(a) K2CO3
(b) Na2CO3
(c)
BaCo3
(d) Li2CO3
Answer
Key:
(d) Li2CO3 II. Short Answer Questions
11th ChemistryIII. Long Answer Questions
11th ChemistryIV. Exercise
11th Chemistry
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