Which one of the following ores is best concentrated by froth – floatation method?

(a)

Magnetite

(b)

Haematite

(c)

Galena

(d)

Cassiterite

Pick out the alloy that contains a non-metal as a constituent in it ________.

(a)

Brass

(b)

Bronze

(c)

Steel

(d)

Invar

The element that does not show catenation among the following p-block elements is ________.

(a)

Carbon

(b)

silicon

(c)

Lead

(d)

germanium

In the brown ring test, brown colour of the ring is due to _______.

(a)

a mixture of No and NO₂

(b)

Nitroso ferrous sulphate

(c)

Ferrous nitrate

(d)

Ferric nitrate

The correct order of increasing oxidizing power in the series _______.

(a)

VO₂⁺ < Cr₂O₇^2- < MnO₄^-

(b)

Cr₂O₇^2- < VO₂⁺ < MnO₄^-

(c)

Cr₂O₇^2- < MnO₄^- < VO₂⁺

(d)

MnO₄^- < Cr₂O₇^2- < VO₂⁺

As per IUPAC guidelines, the name of the complex [Co(en)₂(ONO)Cl]Cl is _______.

(a)

chloro bis ethylenediamine nitrocobalt(III) chloride

(b)

chloridobis(ethane-1, 2-diamine)nitro K-O Cobaltate(III) chloride

(c)

chloridobis(ethane-1, 2-diammine)nitrito K-O Cobalt(II) chloride

(d)

chloridobis(ethane-1, 2-diamine)nitrito K-O Cobalt(III) chloride

Structural formula of tetra aqua dichlorido Chromium (III) chloride _______.

(a)

[Cr(H₂O)₄Cl₂]Cl₂

(b)

[Cr(H₂O)₄Cl₃]

(c)

[(H₂O)₄Cl₂Cr]Cl₂

(d)

[Cl₂(H₂O)₄Cr]Cl₃

Magnetic moment is given by the formula _______.

(a)

\(\sqrt { n(n+1) } \)

(b)

\(\sqrt { n(n+2) } \)

(c)

\(\sqrt { (n+2) } \)

(d)

\(\sqrt { { n }^{ 2 }+(n+2) } \)

Assertion: monoclinic sulphur is an example of monoclinic crystal system
Reason: for a monoclinic system, \(a\neq b\neq c\) and \(\alpha =\gamma ={ 90 }^{ 0 },\beta \neq { 90 }^{ 0 }\) 
Codes:
a) Both assertion and reason are true and 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 assertion and reason are true and 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.

An example of covalent crystalline solid is ______.

(a)

NaI

(b)

AI

(c)

Si

(d)

Ar

The coordination number of each sphere in body centred cubic packing is _______.

(a)

2

(b)

4

(c)

6

(d)

8

The addition of a catalyst during a chemical reaction alters which of the following quantities?

(a)

Enthalpy

(b)

Activation energy

(c)

Entropy

(d)

Internal energy

For a reaction, 2A + B ⟶ 3C, The rate of appearance of C at time 't' is 1.2 x 10^-4 mol L^-1s^-1. Identify the rate of reaction.

(a)

4 x 10^-5mol L^-1s^-1

(b)

4.5 x 10^-1mol L^-1s^-1

(c)

3.6 x 10^-4 mol L^-1s^-1

(d)

None of these

A+B \(\longrightarrow \) C; ∆H = 60 kJ mol^-1 Ea_f = 150 kJ. What is the activation energy of the backward reaction?

(a)

210 kJ

(b)

105 kJ

(c)

90 kJ

(d)

145 kJ

Which order reaction obeys the expression \({ t }_{ \frac { 1 }{ 2 } }\alpha \frac { 1 }{ \left[ A \right] } ?\)

(a)

First

(b)

Second

(c)

Third

(d)

Zero

The addition of a catalyst during a chemical reaction alters which of the following quantities?

(a)

Activation energy

(b)

Entropy

(c)

Internal energy

(d)

Enthalpy

How much time will be taken for 20 gm to reduce 5 g? [R = 2 x 10^-3s^-1 (I order reaction)]

(a)

693.1 s

(b)

693.1 s^-1

(c)

6.931 s

(d)

6.931 s^-1

Which of the above graphs is correct for zero order reactions?

(a)

I, II

(b)

I, III

(c)

I, IV

(d)

II, III

The excess energy which a molecule must possess to become active is known as  _____.

(a)

kinetic energy

(b)

threshold energy

(c)

potential energy

(d)

activation energy

The rate of a reaction is expressed as k[A]₂[B]¹,  the reaction is said to be  _____.

(a)

second order with respect to A

(b)

first order with respect to B

(c)

overall order of the reaction is third order

(d)

all the above

For a complex reaction _____.

(a)

Order of overall reaction is same as molecularity of the slowest step.

(b)

Order of overall reaction is less than the molecularity of the slowest step.

(c)

Order of overall reaction is greater than molecularity of the slowest step.

(d)

None of these above.

When the E_a of a reaction zero then the rate constant of the reaction is equal to _______.

(a)

2.303 K

(b)

\(\frac { K }{ 2.303 } \)

(c)

\(\left( { t }_{ \frac { 1 }{ 2 } } \right) \)

(d)

A

For the reaction N_2(g) + 3H_2(g) ⟶ 2NH_3(g) the rate of the reaction in terms of ammonia is ______.

(a)

\(+\frac { 1 }{ 2 } \frac { -d\left[ { NH }_{ 3 } \right] }{ dt } \)

(b)

\(-\frac { 1 }{ 2 } \frac { d\left[ { NH }_{ 3 } \right] }{ dt } \)

(c)

\(\frac { -d\left[ { NH }_{ 3 } \right] }{ dt } \)

(d)

\(\frac { +d\left[ { NH }_{ 3 } \right] }{ dt } \)

In a second order reaction, if one of the concentration is excess, the order of the reaction is ________ order reaction.

(a)

first

(b)

pseudo first

(c)

third

(d)

zero

Activation energy of a reactant is reduced by ________.

(a)

increased temperature

(b)

reduced temperature

(c)

increased pressure

(d)

reduced pressure