12th Standard Chemistry English Medium Free Online Test One Mark Questions with Answer Key 2020 - Part Eight | QB365

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12th Standard Chemistry English Medium Free Online Test One Mark Questions with Answer Key 2020 - Part Eight

Published on: 13/10/2020

Download Tamil Nadu 12th 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.

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Std: 12th Standard - Chemistry

chapter: - Model Question paper

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Questions:

Multiple Choice Question

25 x 1 = 25

The reciprocal of specific resistance is called _______.

(a)

conductance

(b)

specific conductance

(c)

conductivity

(d)

both specific conductance and conductivity

CH₃CHO and C₆H₅CH₂CHO can be distinguished by ______.

(a)

Tollens reagent

(b)

Fehlings solution

(c)

Benedict

(d)

Iodoform test

Acetone reacting with HCN to form cyanohydrin is ________ type of reaction.

(a)

Nucleophilic addition

(b)

Electrophilic substitution

(c)

Freeradical substitution

(d)

Redox

Which among the following does not give haloform test?

(a)

CH₃CHO

(b)

CH₃COC₂H₅

(c)

CH₃CH₂COCH₂CH₃

(d)

CH₃CH₂COCH₃

Brownian movement of colloidal particles is a ______ property.

(a)

Kinetic

(b)

Electrical

(c)

Optical

(d)

Magnetic

pH of 0.05M H₂SO₄ is _______.

(a)

(b)

2.6990

(c)

1.3010

(d)

1.6990

The ultimate product obtained when glycerol reacts with oxalic acid at 533K is ________.

(a)

formic acid

(b)

glycerol oxalate

(c)

allyl alcohol

(d)

acrolein

Which of the following gives violet colour with neutral ferric chloride solution?

(a)

phenol

(b)

glycerine

(c)

benzyl alcohol

(d)

ethanol

For W/O emulsion, the principle emulsifying agent is _______.

(a)

proteins

(b)

synthetic soaps

(c)

lampblack

(d)

gums

10.

In the reaction Ethanol \(\overset { { PCl }_{ 5 } }{ \longrightarrow } X\overset { alc.KOH }{ \longrightarrow } Y\overset { { H }_{ 2 }{ SO }_{ 4 }/{ H }_{ 2 }O }{ \underset { 298k }{ \longrightarrow } } Z.\) The ‘Z’ is ______.

(a)

ethane

(b)

ethoxyethane

(c)

ethylbisulphite

(d)

ethanol

11.

Which one of the is not a surfactant?

(a)

CH₃ -(CH₂)₁₅ -N⁺ -(CH₃)₂ CH₂Br

(b)

CH₃ -(CH₂)₁₅ -NH₂

(c)

CH₃ -(- CH₂- )-₁₆CH₂ OSO₂^- Na⁺

(d)

OHC-(CH₂)₁₄ -CH₂ -COO^- Na⁺

12.

Zinc can be coated on iron to produce galvanized iron but the reverse is not possible. It is because _______.

(a)

Zinc is lighter than iron

(b)

Zinc has lower melting point than iron

(c)

Zinc has lower negative electrode potential than iron

(d)

Zinc has higher negative electrode potential than iron

13.

Conjugate base for Bronsted acids H₂O and HF are _______.

(a)

OH^- and H₂FH⁺, respectively

(b)

H₃O⁺ and F^-, respectively

(c)

OH^- and F^-, respectively

(d)

H₃O⁺ and H₂F⁺, respectively

14.

Which one of the following is an example of pseudo first order reaction?

(a)

Acid hydrolysis of ester

(b)

Decomposition of HI

(c)

Synthesis of NH₃

(d)

All radioactive transformations

15.

For an exothermic chemical process occurring in 2 steps as
(i) A +B ⟶ X (slow) ;
(ii) X ⟶ AB (fast)
The progress of the reaction can be best described by (x- intermediate).

(a)

(b)

(c)

(d)

None of these

16.

A crystal which has the same unit cell and contains the same lattice points throughout the crystal is_________.

(a)

perfect

(b)

imperfect

(c)

distorted

(d)

both (b) and (c)

17.

Coinage metals are _______.

(a)

normal metals

(b)

transition metals

(c)

active metals

(d)

alkali metals

18.

In the froth-floatation process the collectors such as pine oil and xanthates, etc enhance.

(a)

Non-wettability of the mineral particles in froth.

(b)

Non-wettability of the mineral particles in water

(c)

Non-wettability of the gangue particles in froth

(d)

Non-wettability of the gangue particles in water

19.

Identify the Co-ordination entity in the given complex [Co(NH₃)₄(H₂O)CI]CI₂

(a)

Cl₂

(b)

(NH₃)₄

(c)

[Co(NH₃)₄(H₂O)Cl]

(d)

(H₂O)

20.

Predict the rate law of the following reaction based on the data given below
2A+B⟶C+3D

Reaction number	[A] (min)	[B] (min)	Initial rate (M s^-1)
1	0.1	0.1	x
2	0.2	0.1	2x
3	0.1	0.2	4x
4	0.2	0.2	8x

(a)

rate = k[A]²[B]

(b)

rate = k[A] [B]²

(c)

rate = k[A] [B]

(d)

rate = k[A]^1/2[B]^3/2

21.

The crystal with a metal deficiency defect is ________.

(a)

NaCl

(b)

FeO

(c)

ZnO

(d)

KCl

22.

Which type of isomerism is exhibited by [Pt(NH₃)₂Cl₂]?

(a)

Coordination isomerism

(b)

Linkage isomerism

(c)

Optical isomerism

(d)

Geometrical isomerism

23.

The compound that is used in nuclear reactors as protective shields and control rods is _________.

(a)

Metal borides

(b)

metal oxides

(c)

Metal carbonates

(d)

metal carbide

24.

An element belongs to group 15 and 3^rdperiod of the periodic table, its electronic configuration would be_______.

(a)

1s² 2s² 2p⁴

(b)

1s² 2s² 2p³

(c)

1s² 2s² 2p⁶ 3s² 3p²

(d)

1s² 2s² 2p⁶ 3s² 3p³

25.

Which of the following is used for concentrating ore in metallurgy?

(a)

Leaching

(b)

Roasting

(c)

Froth floatation

(d)

Both (a) and (c)

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Answers Key:

Multiple Choice Question

25 x 1 = 25

(d)
both specific conductance and conductivity

(d)
Iodoform test

(a)
Nucleophilic addition

(a)
Kinetic

(a)
1

(a)
phenol

10.

11.

(b)
CH₃ -(CH₂)₁₅ -NH₂

12.

E^o_Zn²⁺[Zn]= 0.76V and E^o_Fe²⁺[Fe]= -0.44V
Zinc has higher negative electrode potential than iron, iron cannot be coated on zinc

13.

H₂O + H₂O ⇌ H₃O⁺ + OH^-
acid 1 base 1 acid 2 base 2
HF + H₂O ⇌ H₃O⁺ + F^-
acid 1 base 1 acid 2 base 2
∴ Conjugate bases are OH^- and F^- respectively.

14.

(a)
Acid hydrolysis of ester

15.

16.

(a)
perfect

17.

(b)
transition metals

18.

(b)
Non-wettability of the mineral particles in water

19.

20.

rate₁ = k[0.1]ⁿ [0.1]^m ....(1)
rate₂ = k[0.2]ⁿ [0.1]^m ....(2)
(2) (1)
\(=\frac{2x}{x} = \frac{k[0.2]^n [0.1]^m}{k[0.1]^n [0.1]^m}\)
\(= \frac{2x}{x} = 2^n\)
n = 1
rate₃ = k[0.1]ⁿ [0.2]^m ....(3)
rate₄ = k[0.2]ⁿ [0.2]^m ....(4)
\(=\frac{8x}{2x} = \frac{k[0.2]^n [0.2]^m}{k[0.2]^n [0.1]^m}\)
= 8/2 = 2m
m = 2
rate = k[A] [B]²