Some Basic Concepts Of Chemistry - Mole Concept — DPP 3

20 NEET questions from Some Basic Concepts in Chemistry, with answers and explanations. Attempt it as a timed test to get scoring, accuracy breakdown and mistake tracking.

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1
A container of volume V , contains 0.28 g of $\mathrm { N } _ { 2 }$ gas. If same volume of an unknown gas under similar condition of temperature and pressure weighs 0.44 g , the molecular mass of the gas is
  1. A 22
  2. B 44
  3. C 66
  4. D 88
Show answer & explanation

Correct answer: B

$\frac{\mathrm{M}_{\text {gas }}}{\mathrm{M}_{\mathrm{N}_{2}}}=\frac{0.44}{0.28} \\ \mathrm{M}_{\text {gas }}=\frac{0.44}{0.28} \times 28 $
=44
2
1 L of $\mathrm { CO } _ { 2 }$ is passed over hot coke. When the volume of reaction mixture becomes 1.4 L , the composition of reaction mixture is-
  1. A $0.6 \mathrm {~L} \mathrm {~ CO }$
  2. B $0.8 \mathrm {~L} \mathrm {~CO } _ { 2 }$
  3. C $0.6 \mathrm {~L} \mathrm {~CO } _ { 2 }$ and $0.8 \mathrm {~L} \mathrm {~ CO }$
  4. D None
Show answer & explanation

Correct answer: C

Some Basic Concepts Of Chemistry - Mole Concept – NEET-5704 Vol. after = 1 – x + 2x = 1.4
reaction x = 0.4
$\mathrm{V}_{\mathrm{CO}_{2}}$ left = 1 – 0.4 = 0.6 L
$\mathrm{V}_{\mathrm{CO}}$ prepared = 2 × 0.4 = 0.8 L
3
Given below are two statements:
Statement-I : Both 12g of carbon and 27g of Aluminium will have 6.02 × 10$^{23}$ atoms.
Statement-II : Gram atomic mass of an element contains Avogadro's no. of atoms.
In the light of the above statements, choose the most appropriate answer from the options given below:
  1. A Statement-I and II both are correct.
  2. B Statement-I is correct while II is incorrect.
  3. C Both Statement-I and II are incorrect.
  4. D Statement-I is incorrect and II is correct.
Show answer & explanation

Correct answer: A

→ $\mathrm{n}_{\mathrm{C}}=\frac{12}{12}$ = 1 & $\mathrm{n}_{\mathrm{Al}}=\frac{27}{27}$ = 1
Moles are same so number of atoms also
same number of atoms
n × N$_\mathrm{A}$ × 1
1 × N$_\mathrm{A}$ × 1 = N$_\mathrm{A}$ atoms.
→ Gram atomic mass represents mass of 1 mole of atoms & 1 mol has 6.022 × 10$^{23}$ atoms.
4
In a gaseous reaction of the type
$\mathrm { aA } + \mathrm { bB } \longrightarrow \mathrm { cC } + \mathrm { dD }$,
which statement is wrong ?
  1. A A litre of A combines with b litre of B to give C and D
  2. B A mole of A combines with b moles of B to give C and D
  3. C A g of A combines with b g of B to give C and D
  4. D A molecules of A combines with b molecules of B to give C and D
Show answer & explanation

Correct answer: C

$\mathrm { aA } + \mathrm { bB } \longrightarrow \mathrm { cC } + \mathrm { dD }$
mass ratio is not same as coffi. Ratio so statement is wrong statement for this reaction.
5
Given below are two statements:
Statement-I : In the reaction
CH$_{4}$(g) + 2O$_{2}$(g) → CO$_{2}$(g) + 2H$_{2}$O(g)
One mole of CH₄(g) reacts with two moles of O₂(g) to give one mole of CO₂(g) and two moles of H₂O(g).
Statement-II : 1g of CH₄(g) reacts with 2g of O₂(g) to give 1g of CO₂(g) and 2g of H₂O(g).
In the light of the above statements, choose the most appropriate answer from the options given below:
  1. A Statement-I and II both are correct.
  2. B Statement-I is correct while II is incorrect.
  3. C Both Statement-I and II are incorrect.
  4. D Statement-I is incorrect and II is correct.
Show answer & explanation

Correct answer: B

CH₄(g) + 2O₂(g) → CO₂(g) + 2H₂O(g)
→ 1mole CH₄ reacts with 2mole O₂ to produce 1 mole CO₂ & 2 mole H₂O.
→ Coefficients ratio will not be same as mass ratio.
I$^\mathrm{st}$ correct, II$^\mathrm{nd}$ incorrect.
6
12 L of $\mathrm { H } _ { 2 }$ and 11.2 L of $\mathrm { Cl } _ { 2 }$ are mixed and exploded. The composition by volume of mixture is-
  1. A 24 L of $\mathrm { HCl } ( \mathrm { g } )$
  2. B $0.8 \mathrm {~L} \mathrm {~Cl } _ { 2 }$ and $20.8 \mathrm {~L} \mathrm {~HCl } ^ { \circ } ( \mathrm { g } )$
  3. C $0.8 \mathrm {~L} \mathrm {~H } _ { 2 }$ and $22.4 \mathrm {~L} \mathrm {~HCl } ( \mathrm { g } )$
  4. D $22.4 \mathrm {~L} \mathrm {~HCl } ( \mathrm { g } )$
Show answer & explanation

Correct answer: C

Some Basic Concepts Of Chemistry - Mole Concept – NEET-5712 11.2 L of Cl$_{2}$ will react with 11.2 L H$_{2}$ to
product 22.4 L HCl.
Remaining H$_{2}$ = 12 – 11.2 = 0.8 L
7
Given below are two statements:
Statement-I : A molecule of butane, C$_{4}$H$_{10}$ has a mass of 58 amu.
Statement-II : One mole of butane contains 6.022 × 10$^{23}$ molecules and has a mass of 58g.
In the light of the above statements, choose the most appropriate answer from the options given below:
  1. A Statement-I is correct while II is incorrect.
  2. B Statement-I and II both are correct.
  3. C Both Statement-I and II are incorrect.
  4. D Statement-I is incorrect and II is correct.
Show answer & explanation

Correct answer: B

Mass of 1 butane (C$_{4}$H$_{10}$) molecule is 58 amu.
Mass of 1 mole butane = 58 amu × N$_\mathrm{A}$
= N$_\mathrm{A}$ × amu = 1 g = 58g
1 mole has = 6.022 × 10$^{23}$ molecules.
8
When 100 g of ethylene polymerizes to polyethylene according to equation
$\mathrm { nCH } _ { 2 } = \mathrm { CH } _ { 2 } \rightarrow - \left( - \mathrm { CH } _ { 2 } - \mathrm { CH } _ { 2 } - \right) _ { \mathrm { n } }$-. The weight of polyethylene produced will be:-
  1. A $\frac { \mathrm { n } } { 2 } \mathrm {~g}$
  2. B 100 g
  3. C $\frac { 100 } { n } \mathrm {~g}$
  4. D 100 ng
Show answer & explanation

Correct answer: B

Entire mass of ethylene is converted to polyethylene so according to LOMA 100 g
9
A chemical equation is balanced according to the law of -
  1. A Multiple proportion
  2. B Constant composition
  3. C Gaseous volume
  4. D Conservation of mass
Show answer & explanation

Correct answer: D

Conservation of mass
10
Different proportions of oxygen in the various oxides of nitrogen prove the law of -
  1. A Equivalent proportion
  2. B Multiple proportion
  3. C Constant proportion
  4. D Conservation of matter
Show answer & explanation

Correct answer: B

Multiple proportions.
11
Given below are two statements:
Statement-I : For a reaction between 10L H₂(g) and 10L O₂(g), only 10L of liquid water is obtained, under the same conditions of P & T.
Statement-II : When gases combine or are produced in a chemical reaction they do so in a simple ratio by volume as their stoichiometric coefficients, provided that all gases are present under the same conditions of pressure & temperature.
In the light of the above statements, choose the most appropriate answer from the options given below:
  1. A Statement-I and II both are correct.
  2. B Statement-I is correct while II is incorrect.
  3. C Both Statement-I and II are incorrect.
  4. D Statement-I is incorrect and II is correct.
Show answer & explanation

Correct answer: D

Some Basic Concepts Of Chemistry - Mole Concept – NEET-6026O₂ will also left as excess reagent.
Stoichiometric coefficients ratio is same as volume ratio.
I$^\mathrm{st}$ incorrect, II$^\mathrm{nd}$ correct.
12
Given below are two statements; one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : Hydrogen combines with oxygen to form two compounds namely, water and hydrogen peroxide.
Reason (R) : The above example is in accordance with law of multiple proportion.
In the light of the assertion reason statements, choose the most appropriate answer from the options given below :
  1. A If (A) & (R) both are correct and (R) is the correct explanation of (A).
  2. B If (A) & (R) both are correct but (R) is not the correct explanation of (A).
  3. C (A) is correct but (R) is incorrect.
  4. D (A) & (R) both are incorrect.
Show answer & explanation

Correct answer: A

2H₂ + O₂ → 2H₂O
H₂ + O₂ → H₂O₂
Both reaction follows law of multiple proportion A & R both are correct & R is correct explanation of A.
13
An organic compound contains carbon, hydrogen and oxygen. Its elemental analysis gives $38.71 \%$ of C and $9.67 \%$ of H . The empirical formula of the compound would be :-
  1. A $\mathrm { CHO }$
  2. B $\mathrm { CH } _ { 4 } \mathrm { O }$
  3. C $\mathrm { CH } _ { 3 } \mathrm { O }$
  4. D $\mathrm { CH } _ { 2 } \mathrm { O }$
Show answer & explanation

Correct answer: C

Some Basic Concepts Of Chemistry - Mole Concept – NEET-5698 E.F.= CH$_{3}$O
14
If 8 mL of uncombined $\mathrm { O } _ { 2 }$ remain after exploding $\mathrm { O } _ { 2 }$ with 4 mL of hydrogen, the number of mL of $\mathrm { O } _ { 2 }$ originally were -
  1. A 12
  2. B 2
  3. C 10
  4. D 4
Show answer & explanation

Correct answer: C

2H$_{2}$ + O$_{2}$ → 2H$_{2}$O
2vol. H$_{2}$ react with 1 vol. of O$_{2}$
4 ml H$_{2}$ will react with 2 ml of O$_{2}$
Total vol. of O$_{2}$ = VO$_{2}$(reacted) + VO$_{2}$(unreacted)
VO$_{2\mathrm{(total)}}$ = 2 ml + 8 ml = 10 ml
15
In the reaction
$\mathrm { N } _ { 2 } + 3 \mathrm { H } _ { 2 } \longrightarrow 2 \mathrm { NH } _ { 3 }$, ratio by volume of $\mathrm { N } _ { 2 }$, $\mathrm { H } _ { 2 }$ and $\mathrm { NH } _ { 3 }$ is $1 : 3 : 2$. This illustrates law of -
  1. A Definite proportion
  2. B Multiple proportion
  3. C Law of conservation of mass
  4. D Gaseous volumes
Show answer & explanation

Correct answer: D

Gaseous volumes
16
Two flasks A & B of equal capacity of volume contain $\mathrm { NH } _ { 3 }$ and $\mathrm { SO } _ { 2 }$ gas respectively under similar conditions. Which flask has more number of moles:-
  1. A A
  2. B B
  3. C Both have same moles
  4. D None
Show answer & explanation

Correct answer: C

Some Basic Concepts Of Chemistry - Mole Concept – NEET-5725
Same moles
17
The amount of water (g) produced by combustion of 286 g of propane is
  1. A 168 g
  2. B 200 g
  3. C 468 g
  4. D 693 g
Show answer & explanation

Correct answer: C

C$_{3}$H$_{8}$ + 5O$_{2}$ → 3CO$_{2}$ + 4H$_{2}$O
n = $\frac{286}{44}$ = 6.5
1 mol C$_{3}$H$_{8}$ → 4 mol of H$_{2}$O
6.5 mol C$_{3}$H$_{8}$ → 4 × 6.5 mol of H$_{2}$O
$\mathrm{n}_{\mathrm{H}_{2} \mathrm{O}}$ = 26
$\mathrm{W}_{\mathrm{H}_{2} \mathrm{O}}$ = 26 × 18 = 468g
18
26 cc of $\mathrm { CO } _ { 2 }$ are passed over red hot coke. The volume of CO evolved is :-
  1. A 15 cc
  2. B 10 cc
  3. C 32 cc
  4. D 52 cc
Show answer & explanation

Correct answer: D

$\mathrm{C}+\underset{26 \mathrm{~CC}}{\mathrm{CO}_{2}} \rightarrow 2 \mathrm{CO}$
1 Vol. of CO$_{2}$ → 2 Vol. of CO
26 CC of CO$_{2}$ → 2 × 26 CC of CO
V$_\mathrm{CO}$ = 52CC

19
10 mL of gaseous hydrocarbon on combustion give 40 mL of $\mathrm { CO } _ { 2 } ( \mathrm {~g} )$ and 50 mL of $\mathrm { H } _ { 2 } \mathrm { O }$ (vap.). The hydrocarbon is -
  1. A $\mathrm { C } _ { 4 } \mathrm { H } _ { 5 }$
  2. B $\mathrm { C } _ { 8 } \mathrm { H } _ { 10 }$
  3. C $\mathrm { C } _ { 4 } \mathrm { H } _ { 8 }$
  4. D $\mathrm { C } _ { 4 } \mathrm { H } _ { 10 }$
Show answer & explanation

Correct answer: D

Some Basic Concepts Of Chemistry - Mole Concept – NEET-5713From stoichiometry, x = 4, $\frac{y}{2}$ = 5 ⇒ y = 10
Which means C$_{4}$H$_{10}$
20
A compound contains $38.8 \% \mathrm {~C } , 16.0 \% \mathrm {~H }$ and $45.2 \% \mathrm {~N}$. The formula of the compound would be
  1. A $\mathrm { CH } _ { 3 } \mathrm { NH } _ { 2 }$
  2. B $\mathrm { CH } _ { 3 } \mathrm { CN }$
  3. C $\mathrm { C } _ { 2 } \mathrm { H } _ { 5 } \mathrm { CN }$
  4. D $\mathrm { CH } _ { 2 } ( \mathrm { NH } ) _ { 2 }$
Show answer & explanation

Correct answer: A

Some Basic Concepts Of Chemistry - Mole Concept – NEET-5690E.F. $=\mathrm{CH}_{5} \mathrm{N}$ or $\mathrm{CH}_{3} \mathrm{NH}_{3}$

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