One mole of ${\rm{C}}{{\rm{O}}_2}$ contains

3 g atoms of ${\rm{C}}{{\rm{O}}_2}$

$18.1 \times {10^{23}}$ molecules of ${\rm{C}}{{\rm{O}}_2}$

$6.02 \times {10^{23}}$ atoms of O

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NEET • CHEMISTRY • SOME BASIC CONCEPTS OF CHEMISTRY

Some basic concepts of chemistry practice · Mixed difficulty

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Showing 1-30 of 313 questions

1 Easy

1 of 313

Understanding +4 | -1

While titrating dilute

HCl

solution with aqueous NaOH, which of the following will not be required?

View answer and explanation

Correct option: C

Bunsen burner and measuring cylinder

Option C is correct because a Bunsen burner and measuring cylinder are not typically required for a simple acid-base titration.

2 Easy

2 of 313

Application +4 | -1

Which has the maximum number of molecules among the following

View answer and explanation

Correct option: C

8\,g\,\,{H_2}

Option C (

8\,g\,\,{H_2}

) is correct because it has the highest number of moles, and therefore the largest number of molecules.

3 Medium

3 of 313

Understanding +4 | -1

One mole of

\mathrm{C}{\mathrm{O}_2}

contains

View answer and explanation

Correct option: D

6.02 \times {10^{23}}

atoms of C

The correct answer is D (

6.02 \times {10^{23}}

atoms of C) because one mole of any substance contains Avogadro's number of entities, and in one mole of

CO_2

there is one mole of carbon atoms.

4 Medium

4 of 313

Understanding +4 | -1

The number of molecules present in 1 mL of gas or vapour at STP is:

View answer and explanation

Correct option: C

Both (1) and (2)

Option C (Both (1) and (2)) is correct because the number of molecules present in 1 mL of gas or vapor at STP is called Loschmidt's number and is equal to approximately 2.687 × 10¹⁹ per mL.

5 Easy

5 of 313

Application +4 | -1

The specific heat of an element of atomic weight 32 is likely to be:

View answer and explanation

Correct option: C

0.20 cal/g

Option B (0.24 cal/g) is correct because, according to Dulong-Petit's law, the specific heat of an element is approximately 6.4 cal/(mol·K) divided by its atomic weight.

6 Easy

6 of 313

Remembering +4 | -1

The significant figures in 3400 are

View answer and explanation

Correct option: A

Option A (2) is correct because only the '3' and '4' are significant; trailing zeros without a decimal point are ambiguous.

7 Medium

7 of 313

Analyzing +4 | -1

Statement I: Equimolar solutions of

\mathrm{H}_3 \mathrm{PO}_3

and

\mathrm{H}_2 \mathrm{SO}_4

are not equinormal.

Statement II: Both are dibasic acid and Molarity

\times 2=

normality.

View answer and explanation

Correct option: D

Statement I is false; Statement II is true

Option D (Statement I is false; Statement II is true) is correct because H3PO3 is a dibasic acid while H2SO4 is also a dibasic acid, therefore equimolar solutions will not be equinormal.

8 Medium

8 of 313

Application +4 | -1

In the equation,

\mathrm{SnC}{\mathrm{l}_2} + 2\mathrm{HgC}{\mathrm{l}_2} \to \mathrm{H}{\mathrm{g}_2}\mathrm{C}{\mathrm{l}_2} + \mathrm{SnC}{\mathrm{l}_4}.

. The equivalent weight of stannous chloride (molecular weight = 190) will be :

View answer and explanation

Correct option: B

Option B (95) is correct because the equivalent weight is calculated by dividing the molecular weight by the change in oxidation state, which is 2 in this case.

9 Hard

9 of 313

Application +4 | -1

The number of

C{l^ - }

ions in 100 ml of 0.001M HCl solution is

View answer and explanation

Correct option: C

6.022 \times {10^{19}}

Option C (

6.022 \times {10^{19}}

) is correct because the number of chloride ions is calculated from the molarity and volume of the HCl solution.

10 Medium

10 of 313

Analyzing +4 | -1

Which of the following contains greatest number of oxygen atoms?

View answer and explanation

Correct option: D

All have the same number of atoms

Option D (All have the same number of atoms) is correct because 1 g of any element will have the same number of atoms if we're considering individual atoms of oxygen.

11 Medium

11 of 313

Application +4 | -1

An ore contains 1.34% of the mineral argentite,

\mathrm{A}{\mathrm{g}_2}\mathrm{S}

, by mass. How many gram of this ore would have to be processed in order to obtain 1.00 g of pure solid silver, Ag?

View answer and explanation

Correct option: B

85.7 g

Option B (85.7 g) is correct because it involves calculating the mass of ore needed based on the percentage of argentite and the stoichiometry of silver in argentite.

12 Medium

12 of 313

Analyzing +4 | -1

In the reaction of oxalate with permanganate in acidic medium. The number of electrons involved in producing one molecule of

C{O_2}

View answer and explanation

Correct option: C

Option C (1) is correct because the oxidation of oxalate (

C_2O_4^{2-}

) to carbon dioxide (

CO_2

) involves the loss of one electron per carbon atom.

13 Hard

13 of 313

Understanding +4 | -1

Assertion:

\mathrm{CO}

and

\mathrm{C}_2 \mathrm{H}_2

both can be absorbed in ammoniacal

\mathrm{CuCl}

.
Reason:

\mathrm{CH}_4

is absorbed on animal charcoal.

View answer and explanation

Correct option: D

Both Assertion and Reason are correct but Reason is not correct explanation of Assertion

Option D (Both Assertion and Reason are correct but Reason is not correct explanation of Assertion) is correct because both statements are true, but unrelated.

14 Easy

14 of 313

Remembering +4 | -1

Molarity is expressed as:

View answer and explanation

Correct option: B

\mathrm{Mol\; litr}{\mathrm{e}^{ - 1}}

Option B is correct because molarity is defined as the number of moles of solute per liter of solution (mol/L).

15 Hard

15 of 313

Application +4 | -1

If the mass percentage of

\mathrm{Cu}

in an enzyme is

0.1270 \%

, then the minimum molecular mass of the enzyme will be (atomic mass of Copper

=63.54

)

View answer and explanation

Correct option: A

50,000 \mathrm{~u}

Option A (

50,000 \mathrm{~u}

) is correct because it is calculated by assuming there is one copper atom per enzyme molecule and using the mass percentage to determine the minimum molecular mass.

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16 Easy

16 of 313

Understanding +4 | -1

The law of definite proportions is not applicable to nitrogen oxide because

View answer and explanation

Correct option: C

Nitrogen equivalent weight is variable

Option C (Nitrogen equivalent weight is variable) is correct because nitrogen can exhibit different oxidation states and thus have different equivalent weights in different nitrogen oxides, violating the law of definite proportions.

17 Easy

17 of 313

Remembering +4 | -1

The least count of burette used normally in laboratory is :

View answer and explanation

Correct option: A

0.1 mL

Option A (0.1 mL) is correct because the least count of a standard laboratory burette is typically 0.1 mL.

18 Hard

18 of 313

Application +4 | -1

At constant

{T}

and

{P}, 5.0 \mathrm{~L}

{SO}_2

are reacted with

3.0 \mathrm{~L}

{O}_2

according to the following equation,

2 {SO}_2(\mathrm{~g})+{O}_2(\mathrm{~g}) \rightarrow 2 {SO}_3(\mathrm{~g})

. The volume of the reaction mixture at the completion of the reaction is

View answer and explanation

Correct option: C

5.5 L

Option C (5.5 L) is correct. By identifying the limiting reactant and calculating the volume of the products and remaining reactants, we can determine the final volume of the reaction mixture.

19 Medium

19 of 313

Remembering +4 | -1

Molar mass is maximum for

View answer and explanation

Correct option: B

Sulphur

Option B (Sulphur) is correct because Sulphur exists as S8, which has a higher molar mass than the other options in their standard forms.

20 Easy

20 of 313

Application +4 | -1

Which one of the followings has maximum number of atoms ?

View answer and explanation

Correct option: D

\mathrm{1}\,\,\mathrm{g}

\mathrm{Li}\,\left( \mathrm{s} \right)

[ Atomic mass of

Li = \mathrm{ 7}

]

Option D (

\mathrm{1}\,\mathrm{g}

\mathrm{Li}\,\left( \mathrm{s} \right)

) is correct because it has the highest number of moles, and therefore the largest number of atoms.

21 Medium

21 of 313

Analyzing +4 | -1

A: For a given solution (density

=1 \mathrm{gm} / \mathrm{ml}

), molality is greater than molarity.

R: Molarity involves volume of solution while molality involves mass of solvent.

View answer and explanation

Correct option: A

Both A and R are correct and R is the correct explanation of A.

Option B (Both A and R are correct and R is the correct explanation of A) is incorrect. For a given solution with density = 1 g/mL, molality is less than molarity, not greater. The reason is correct, molarity involves volume of solution, while molality involves mass of solvent.

22 Medium

22 of 313

Application +4 | -1

There are two isotopes of an element with atomic massz. Heavier one has atomic mass

z + 2

and lighter one has

z -1

, the abundance of lighter one is

View answer and explanation

Correct option: A

66.6\%

Option A (

66.6\%

) is correct because it is calculated using the weighted average formula for atomic mass, solving for the abundance of the lighter isotope.

23 Easy

23 of 313

Application +4 | -1

The normality of one molar sodium carbonate solution is:

View answer and explanation

Correct option: A

Option A (2) is correct because the normality of sodium carbonate is twice its molarity due to its n-factor being 2.

24 Easy

24 of 313

Understanding +4 | -1

Given P = 0.0030m, Q = 2.40m, R = 3000m, Significant figures in P, Q and R are respectively

View answer and explanation

Correct option: B

2, 3, 4

Option B is correct because significant figures are counted from the first non-zero digit, and trailing zeros without a decimal point are ambiguous.

25 Hard

25 of 313

Analyzing +4 | -1

Choose the corrcct statements.

(a) Double decomposition method is based on the law of equivalent.

(b) For a reaction,

{P}_{m} {Q}_{{n}}+{R}_o {S}_{{p}} \longrightarrow \text{products}

If amount of

P_m Q_n

reactcd

=w_1

gm

and amount of

R_o S_p

reacted

=w_2

gm, then

\frac{w_1}{w_2}=\frac{\text {Equivalent wt. of } R_o S_p}{\text {Equivalent wt. of } P_{m} Q_{n}}

P_{m} Q_n+R_o S_p \longrightarrow \text{products}

If amount of

P_m Q_n

reacted

=w_1

gm

and amount of

R_o S_p

reacted

=w_2

gm, then

\frac{w_1}{w_2}=\frac{\text {Equivalent wt. of } P_m Q_n}{\text {Equivalent wt. of } R_o S_p}

(d) 1 equivalent of oxygen

=16 \mathrm{~gm}

View answer and explanation

Correct option: D

a and c are correct

Option D (a and c are correct) is correct because double decomposition reactions are based on the law of equivalents, and the ratio of reacted masses is equal to the ratio of their equivalent weights.

26 Medium

26 of 313

Application +4 | -1

0.2

g of a sample of

{\mathrm{H}_2}{\mathrm{O}_2}

required

10

mL of

N\mathrm{KMn}{\mathrm{O}_4}

in a titration in the presence of

{\mathrm{H}_2}\mathrm{S}{\mathrm{O}_4}\mathrm{.}

. Purity of

{\mathrm{H}_2}{\mathrm{O}_2}

is :

View answer and explanation

Correct option: B

85\%

Option B (

85\%

) is correct because it is the correct purity of H2O2 calculated using the titration data and stoichiometry.

27 Easy

27 of 313

Understanding +4 | -1

Both natural and synthetic sample of cupric carbonate contains same percentage of copper and carbon by mass. This fact is based on

View answer and explanation

Correct option: B

Law of definite proportion

The correct answer is B (Law of definite proportion) because a given compound always contains exactly the same proportion of elements by mass, regardless of its source.

28 Easy

28 of 313

Application +4 | -1

Maximum number of atoms are present in

View answer and explanation

Correct option: A

8g\,C{H_4}

Option A (

8g\,C{H_4}

) is correct because it contains the highest number of moles of molecules, and each molecule has a significant number of atoms.

29 Medium

29 of 313

Remembering +4 | -1

Number of significant figures in 3.06 is

View answer and explanation

Correct option: D

Option D (3) is correct because in 3.06, all digits are significant, including the zero between the 3 and the 6.

30 Medium

30 of 313

Application +4 | -1

If 6.3 g of

NaHC{O_3}

are added to 15.0 g

\mathrm{C}{\mathrm{H}_3}\mathrm{COOH}

solution, the residue is found to weight 18.0 g. what is the mass of

C{O_2}

released in the reaction?

View answer and explanation

Correct option: B

3.3 g

Option C (2.6 g) is correct because it uses the law of conservation of mass to calculate the mass of CO2 released.

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Key Takeaways

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