Basic Concepts of Chemistry and Chemical Calculations important one mark questions

Download Tamil Nadu 11th Standard Chemistry question papers, model tests, one-mark questions, important questions, and public exam papers in PDF format. Free study materials and answer keys for TN State Board students.

Questions:

Multiple Choice Question

43 x 1 = 43

How many moles of magnesium phosphate Mg₃(PO₄)₂ Will Contain 0.25 moles of oxygen atoms?

(a)

0.02

(b)

3.125 x 10^-2

(c)

1.25 x 10^-2

(d)

2.5 x 10^-2

If a beaker holds 576g of water, what will be the gram molecules of water in that beaker?

(a)

23 gram molecule

(b)

23%

(c)

32%

(d)

32 gram molecule

Calculate the percentage of N in ammonia molecule.

(a)

121.42%

(b)

28.35%

(c)

82.35%

(d)

28.53%

Match the following prefixes with their multiples.

Equivalent Mass(E)		Molecular Mass (M)
A	E_kMnO4(Acidic)	1	M/2
B	E_kMnO4(Neutral)	2	M
C	E_H3PO2	3	M/3
4	E_H3PO3	4	M/5

(a)

A	B	C	D
4	3	2	1

(b)

A	B	C	D
4	2	1	3

(c)

A	B	C	D
3	4	2	1

(d)

A	B	C	D
3	1	4	2

In the reaction to NH₃ + H₂O \(\longrightarrow \) \({ NH }_{ 4 }^{ + }+O\overline { H } \), NH₃ is acidic in. the reason for its acidic is_____

(a)

Acceptance of one ^H+from water

(b)

A release of one OH^-ion

(c)

Due to the nitrogen atom

(d)

All the above

What will be the basicity of H₃BO₃, which is not a protic acid?

(a)

One

(b)

Two

(c)

Three

(d)

Four

One 'U' stands for the mass of ______________.

(a)

An atom of carbon-12

(b)

1/12^th of the carbon-12

(c)

1/12th of a hydrogen atom

(d)

One atom of any of the element

The empirical formula and molecular mass of a compound are CH₂O and 180g respectively. What will be the molecular formula of the compound?

(a)

C₉H₁₉0

(b)

CH₂O

(c)

C₆H₁₂O₆

(d)

C₂H₄O₂

Atomicity of nitrogen is __________.

(a)

(b)

(c)

(d)

Zero

10.

Unit of Avogadro's number is _______________.

(a)

mol

(b)

(c)

mol ^-1

(d)

No unit

11.

One mole of Sulphuric acid contains _______oxygen atoms

(a)

4 x 10²³

(b)

4 x 6.023 x 10^-23

(c)

4 x 6.023 x 10²³

(d)

4 x 6.023 x 10³²

12.

The volume occupied by any gas at S.T.P. is_____

(a)

22.4 litres

(b)

2.24 litres

(c)

224 litres

(d)

0.224 litres

13.

Statement I: an Equivalent mass of Mg is determined by Oxide Method
Statement II: Molecular mass is calculated using vapour density

(a)

Both the statements are individually true

(b)

Both the statements are individually true and statement II is the correct explanation of statement I.

(c)

Statement I is true but statement It is false.

(d)

Statement I is false but statement II is true

14.

12 g of carbon-12 contains_____carbon atoms

(a)

6.022\(\times\)10²³

(b)

(c)

(d)

12.022\(\times\)10^-23 kg

15.

1 amu = _____________.

(a)

1.6605\(\times\)10^-25 kg

(b)

1.6605\(\times\)10^-26 kg

(c)

1.6605\(\times\)10^-27 kg

(d)

1.6605\(\times\)10^-28 kg

16.

Atoms are too small with a diameter of 10^-10 m and weigh approximately ______________.

(a)

10^-27 kg

(b)

10^-27 g

(c)

10^-31 kg

(d)

10^-31

17.

Match list I with list II and identify the correct code.

List I		List II
A	Bronze	1	Element
B	Table Salt	2	Homogeneous mixture
C	Gold	3	Alloy
D	Petrol	4	Compound

(a)

A	B	C	D
1	4	2	3

(b)

A	B	C	D
3	4	1	2

(c)

A	B	C	D
2	3	4	1

(d)

A	B	C	D
4	2	3	1

18.

Which form of based on physical characteristics possess neither definite volume nor definite shape?

(a)

Solids

(b)

Liquids

(c)

Gases

(d)

Both (a) and (b)

19.

Which among the following statement(s) describe an element?
i) It is a pure substance which could be split into two or more simpler substance.
ii) It is a pure substance which cannot be split into simpler substance
iii) It's composition is not uniform
iv) All the above

(a)

only (iv)

(b)

only (ii)

(c)

(ii) and (iii)

(d)

(i) and (iii)

20.

The characteristic feature of orderly arrangement of molecules belongs to ______________.

(a)

Solids

(b)

Liquid

(c)

Gases

(d)

None of these

21.

Identify the incorrect statement about a compound.

(a)

A molecule cannot be separated into its constituent elements by physical methods of separation

(b)

A molecule of a compound has atoms of different elements

(c)

A compound retains the physical properties of its constituent element

(d)

The ratio of atoms of different elements in a compound is fixed

22.

The solid state of matter is converted into gas by

(a)

sublimation

(b)

deposition

(c)

freezing

(d)

condensation

23.

Match the list I with List II and select the correct answer using. the code given below the lists.

List I		List II
A	Diamond	1	Heterogeneous mixture
B	Aerated drinks	2	Element
C	Distilled water	3	Homogeneous mixture
D	Sand	4	Compound

(a)

A	B	C	D
2	3	4	1

(b)

A	B	C	D
4	3	1	2

(c)

A	B	C	D
3	1	4	2

(d)

A	B	C	D
2	1	4	3

24.

Consider the following statements
i) Matter possesses mass.
ii) 22-carat gold is a mixture.
iii) Dry ice is a compound.
Which of the following statement(s) given above is/ are correct?

(a)

1 & 3

(b)

Only 1

(c)

1 & 2

(d)

1,2, & 3

25.

Identify the redox reaction taking place in a beaker.

(a)

Zn_(s)+ Cu²⁺_(aq) \(\longrightarrow\) Zn²⁺_(aq) + Cu_(s)

(b)

Cu_(s) + 2Ag⁺_(aq) \(\longrightarrow\) Cu²⁺_(aq) + 2Ag_(s)

(c)

Cu_(s) + Zn²⁺_(aq) \(\longrightarrow\) Zn_(s) + Cu²⁺ _(aq)

(d)

2Ag_(s) + cu²⁺_(aq) \(\longrightarrow\) 2Ag⁺_aq + Cu_(s)

26.

In which of the following reactions, hydrogen peroxide acts as an oxidising agent?

(a)

I₂+ H₂O₂ + 20H^- \(\longrightarrow\) 21- + 2H₂O + O₂

(b)

PbS + 4H₂O₂ \(\longrightarrow\) PbSO₄ + 4H₂O

(c)

2MnO₄^-+ 3H₂O₂ \(\longrightarrow\) 2MnO₂ + 3O₂ + 2H₂O + 2OH^-

(d)

HOCI + H₂O₂ \(\longrightarrow\) H₂O⁺ + Cl^- + O₂

27.

The change in the oxidation number of S in H₂S and SO₂,in the following industrial reaction:
2H₂S_(g) + SO_2(g) \(\longrightarrow\) 3S_(s) + H2O_(g)

(a)

-2 to 0, +4 to 0

(b)

-2 to 0, +4 to -1

(c)

-2 to -1, +4 to 0

(d)

-2 to -1, +4 to -2

28.

Identify the correct statements with reference to the given reaction
P₄ + 3OH^- + 3H₂O \(\longrightarrow\) PH₃ + 3H₂PO₂^-
(i) Phosphorous is undergoing reduction only
(ii) Phosphorous is undergoing oxidation only
(iii) Phosphorous is undergoing both oxidation and reduction.
(iv) Hydrogen is undergoing neither oxidation nor reduction.

(a)

only (iii)

(b)

both (iii) and (iv)

(c)

only (i)

(d)

None of these

29.

Maximum oxidation state is present in the central metal atom of which compound

(a)

CrO₂Cl₂

(b)

MnO₂

(c)

[Fe(CN)₆]^3-

(d)

MnO

30.

Match the items in column list-I with relevant items in list-II.

List-I		List-II
A	Ions having positive charge	1	anion
B	Ions having negative charge	2	-1
C	Oxidation number of fluorine in NaF	3	0
D	The sum of oxidation number of all atoms in a neutral molecule	4	cation

(a)

A	B	C	D
3	4	2	1

(b)

A	B	C	D
1	2	3	4

(c)

A	B	C	D
2	3	4	1

(d)

A	B	C	D
4	1	2	3

31.

Match the list-I with list-II and select the correct answer using the code given below the lists.

List-I		List-II
A	Cr₂O₇^2-	1	+5
B	MnO₄^-	2	+6
C	VO₃^-	3	+3
D	FeF₆³⁺	4	+7

(a)

A	B	C	D
3	1	4	2

(b)

A	B	C	D
4	3	2	1

(c)

A	B	C	D
2	4	1	3

(d)

A	B	C	D
3	2	1	4

32.

Identify the correct statement(s) with respect to the following reaction :
Zn + 2HCl \(\longrightarrow\) ZnCl₂ + H₂
(i) Zinc is acting as an oxidant
(ii) Chlorine is acting as a reductant
(iii) Hydrogen is not acting as an oxidant
(iv) Zn is acting as a reductant

(a)

only (ii)

(b)

only (iv)

(c)

both (ii) and (iii)

(d)

both (ii) and (i)

33.

Which of the following statement(s) is/are not true about the following decomposition reaction.
2KClO₃ \(\longrightarrow\) 2KCl + 3O₂
(i) Potassium is undergoing oxidation
(ii) Chlorine is undergoing oxidation
(iii) Oxygen is reduced
(iv) None of the species are undergoing oxidation and reduction.

(a)

only (iv)

(b)

(i) and (iv)

(c)

(iv) and (iii)

(d)

All of these

34.

Identify disproportionation reaction

(a)

CH₄ + 2O₂ \(\longrightarrow\) CO₂+ 2H₂O

(b)

CH₄ + 4Cl₂ \(\longrightarrow\) CCl₄ + 4HCI

(c)

2F₂+ 2OH \(\longrightarrow\) 2F^-+ OF₂+ H₂O

(d)

2NO₂ + 2OH^- \(\longrightarrow\) NO^-₂ + NO^-₃ + H₂O

35.

Rusting of iron articles is an example of ___________ reaction

(a)

Combustion

(b)

decomposition

(c)

redox

(d)

hydrolysis

36.

Consider the following statements :
(i) Oxidation number of He = zero
(ii) Increase in oxidation number results in reduction.
(iii) The substance undergoing the increase in oxidation number is reducing agent.
Which among the above statement(s) is/are correct?

(a)

only (i)

(b)

(ii) and (iii)

(c)

(i) and (iii)

(d)

only (ii)

37.

Among the three metals, zinc, copper and silver, the electron releasing tendency decreases in the following order.

(a)

zinc > silver > copper

(b)

zinc > copper > silver

(c)

silver > copper > zinc

(d)

copper > silver > zinc

38.

The oxidation number of Cr in Cr₂O₇^2- _______ is

(a)

(b)

-6

(c)

(d)

-7

39.

The oxidation number of hydrogen in LiH is _________

(a)

(b)

-1

(c)

(d)

-2

40.

The oxidation number of oxygen in O₂ is__________

(a)

(b)

(c)

(d)

-2

41.

Assertion : Fluorine has an oxidation state of - 1 in all its compounds.
Reason : Fluorine is the most electronegative element of the periodic table.

(a)

Both assertion and reason are correct and the reason is the correct explanation for the assertion.

(b)

Both assertion and reason are correct but reason is not the correct explanation for the assertion

(c)

Assertion is true but reason are false.

(d)

Both assertion and reason are false.

42.

Fe2 + \(\longrightarrow\) Fe³⁺ + e^- is a ________ reaction.

(a)

redox

(b)

reduction

(c)

oxidation

(d)

decomposition

43.

The oxidation state of a element in its uncombined state is

(a)

zero

(b)

(c)

-1

(d)

none

Assertion and reason

7 x 2 = 14

44.

Assertion: Oxalic acid is a dibasic acid
Reason: It contains two basic radicals
Codes:
(a) Both assertion and reason are correct and reason is the correct explanation for assertion.
(b) Both assertion and reason are correct but reason is not the correct explanation for assertion
(c) Assertion is true but reason is false.
(d) Both assertion and reason is false.

(a)

Both assertion and reason are correct and reason is the correct explanation for assertion.

(b)

Both assertion and reason are correct but reason is not the correct explanation for assertion

(c)

Assertion is true but reason are false

(d)

Both assertion and reason are false

45.

Assertion: The ash produced by burning paper in air is lighter than the original mass of paper.
Reason: he residue left after combustion of a chemical entity is always lighter
Codes:
(a) Both assertion and reason are correct and reason is the correct explanation for assertion.
(b) Both assertion and reason are correct but reason is not the correct explanation for assertion
(c) Assertion is true but reason is false.
(d) Both assertion and reason is false.

(a)

Both assertion and reason are correct and reason is the correct explanation for assertion.

(b)

Both assertion and reason are correct but reason is not the correct explanation for assertion

(c)

Assertion is true but reason are false

(d)

Both assertion and reason are false

46.

Assertion: The number of oxygen atoms in 16g of oxygen and 16g of ozone is the same
Reason Each of the species represent 1g atom of oxygen
Codes:
(a) Both assertion and reason are correct and the reason is the correct explanation for an assertion
(b) Both assertion and reason are correct but a reason is not the correct explanation for assertion
(c) Assertion is true but reason is false.
(d) Both assertion and reason is false.

(a)

Both assertion and reason are correct and the reason is the correct explanation for an assertion

(b)

Both assertion and reason are correct but a reason is not the correct explanation for assertion

(c)

Assertion is true but reason are false.

(d)

Both assertion and reason are false

47.

Assertion: The atomic masses of most of the elements. are fractions.
Reason: The atomic mass represents the ratio of the average mass of the atom to one avogram.
Codes:
(a) Both assertion and reason are correct and the reason is the correct explanation for assertion
(b) Both assertion and reason are correct but the reason is not the correct explanation for an assertion
(c) Assertion is true but reason is false
(d) Both assertion and reason is false

(a)

Both assertion and reason are correct and the reason is the correct explanation for assertion

(b)

Both assertion and reason are correct but the reason is not the correct explanation for an assertion

(c)

Assertion is true but reason are false

(d)

Both assertion and reason are false

48.

Assertion: An element has a fractional atomic mass.
Reason: An element exists as isotope
Codes:
(a) Both assertion and reason are correct and reason is the correct explanation for the assertion
(b) Both assertion and reason are correct but reason is not the correct explanation for an assertion
(c) Assertion is true but reason is false.
(d) Both assertion and reason are false

(a)

Both assertion and reason are correct and reason is the correct explanation for the assertion

(b)

Both assertion and reason are correct but reason is not the correct explanation for an assertion

(c)

Assertion is true but reason is false.

(d)

Both assertion and reason are false

49.

Assertion (A): In the reaction between potassium permanganate and potassium iodide, permanganate ions act as oxidising agent.
Reason (R): Oxidation state of manganese changes from +2 to +7 during the reaction.
Codes:
(a) Both A and R are true and R explains A
(b) Both A and R are true but R does not explain A
(c) A is true but R is false
(d) Both A and R are false

(a)

Both A and R are true and R explains A

(b)

Both A and R are true but R does not explain A

(c)

A is true but R is false

(d)

Both A and R are false

50.

Assertion (A): Among halogens fluorine is the best oxidant.
Reason (R): Fluorine is the most electronegative atom.
Codes:
(a) both assertion and reason are true and the 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

(a)

Both A and R are true and R explains A

(b)

Both A and R are true but R does not explain A

(c)

A is true but R is false

(d)

Both A and R are false