What will be the pH of a solution formed by mixing 50 ml of 0.5 M HCl solution and 150 ml of 0.5 M NaOH solution and 300 ml H₂O ?

13
12.7
7
11

Solution

The number of isomers of the compound with molecular formula C₂H₂Br₂ is

Solution

Which of the following statements about primary amines is‘False’ ?

Alkylamines are stronger bases than aryl amines
Alkyl amines react with nitrous acid to produce alcohols
Aryl amines react with nitrous acid to produce phenols
Alkyl amines are stronger bases than ammonia

Solution

Aryl amines do not produce phenol on treatment with nitrous acid.

How many moles of magnesium phosphate, Mg₃(PO₄)₂ will contain 0.25 mole of oxygen atoms?

1.25 × 10^–2
2.5 × 10^–2
0.02
3.125 × 10^–2

Solution

1 Mole of Mg₃(PO₄)₂ contains 8 mole of oxygen atoms
∴8 mole of oxygen atoms = 1 mole of Mg₃(PO₄)₂
0.25 mole of oxygen atom = \(\frac{1}{8}\) × 0.25 mole of Mg₃(PO₄)
=3.125 × 10^-2mole of Mg₃(PO₄)₂

The K.E. for 14 g of nitrogen gas at 127°C is nearly (molecular mass of nitrogen is 28 g/mole) and gas constant is 8.31 J/molK)

8.3 kJ
4.15 kJ
2.5 kJ
3.3 kJ

Solution

K. E of n moles of N₂ gas = ³⁄₂nRT

Here n = ¹⁴⁄₂₈ = ¹⁄₂ moles

R = 8.31 J/mol/K

T = 127°C = 400K

∴ KE = ³⁄₂ × ¹⁄₂ × 8.31 × 400J

= 2493.0 J = 2.493 kJ ≅ 2.5 kJ

Solution

K₁ and K₂ are equilibrium constant for reactions (i) and (ii)

N_2(g) + O_2(g) ⇌ 2NO_(g) ……..(i)

NO_(g) ⇌ ¹⁄₂N_2(g) + ¹⁄₂O_2(g) ……..(ii)

Then,

\(K_{1} = \left (\frac{1}{K_{2}} \right )^{2}\)
K₁ = K₂²
\(K_{1} = \left (\frac{1}{K_{2}} \right )\)
K₁ = K₂⁰

Solution

For reaction (i)

\(K_{1} = \frac{\left [ NO \right ]^{2}}{\left [ N_{2} \right ]\left [ O_{2} \right ]}\)

and for reaction (ii)

\(K_{2} = \frac{\left [ N_{2} \right ]^{1/2}\left [ O_{2} \right ]^{1/2}}{\left [ NO \right ]}; K_{1} = \left (\frac{1}{K_{2}^{2}} \right )\)

For a reaction Ag₂O(s)→2Ag+O, the value of ΔH =132.6 kJ, ΔS =66 JK^-1mol^-1 The free energy change for the reaction will be zero at which of the temperature :

2000 K
2009 K
2023 K
2029 K

Solution

ΔG=ΔH-TΔS
0 = 132.6 × 1000 – T × 66
\(T=\frac{132.6\times 1000}{66}=2000K\)

Which one of the following is correctly matched?

Emulsion-smoke
Gel-butter
Aerosol-hair cream
Sol-whipped cream

Solution

Butter is an example of gel.

The ease of liquefaction of noble gases increases in the order

He < Ne
Xe
Kr
Ar < Kr < Xe < Ne < He

Solution

As size increases, van der Waal's forces of attraction between noble gas atoms also increases. Consequently,ease of their liquefaction increases.

The rate constant of first order reaction is 3 × 10^-6 per second.The initial concentration is 0.10 M. The initial rate is:

3× 10^-7 moles/litre/sec
3 × 10^-8 moles/litre/sec
3× 10^-5 moles/litre/sec
3 × 10^-8 moles/litre/sec

Solution

Heavy water reacts respectively with CO₂, SO₃, P₂O₅ and N₂O₅ to give the compounds:

D₂CO₃, D₂SO₄, D₃PO₂, DNO₂
D₂CO₃, D₂SO₄, D₃PO₄, DNO₂
D₂CO₃, D₂SO₃, D₃PO₄, DNO₂
D₂CO₃, D₂SO₄, D₃PO₄, DNO₃

These are Assertion-Reason type questions.Question contains two statements:Statement-1 (Assertion) and Statement-2 (Reason). Answer these question from the following four options.

Statement 1 :Internal energy is an extensive property.
Statement 2 :Internal energy depends upon the amount of the system.

Statement-1 is True, Statement-2 is True, Statement-2 is a correct explanation for Statement-1
Statement-1 is True, Statement-2 is True Statement-2 is NOT a correct explanation for Statement-1
Statement - 1 is True, Statement-2 is False
Statement -1 is False, Statement-2 is True

Solution

The properties whose magnitude depends upon the quantity of matter present in the system are called extensive properties eg, internal energy.

Hydrogen bonding could not affect the boiling point of:

CH₃OH
HI
H₂O
NH₃

Solution

The compounds having O or F or N along with hydrogen show hydrogen bonding and have high boiling points. So HI does not form hydrogen bonds and its boiling point is not affected.

Which is known as ‘Third poison of environment’ and also creates ‘Blue baby syndrome’

Nitrate present in water
Phosphate and detergents found in water
Cynide
Pesticides

In which of the following reactions, there is no change in valency?

4 KClO₃→3KClO₄ + KCl
SO₂+ 2H₂S→2H2₂O + 3S
BaO₂+ H₂SO₄→BaSO₄ + H₂O₂
3 BaO + O₂→2 BaO₂

Solution

In this reaction, none of the elements undergoes a change in oxidation number or valency.

Solution

In (a), (b) and (c) H₂O₂ acts as oxidising agent

Successive addition of electronic shells in case of elements of 17th group causes a increase in

electronegativity
ionization energy
ease of formation of unipositive ion
oxidizing power

An aqueous solution of potash alum gives :

two types of ions
only onetype of ion
four types of ions
three types of ions

Solution

K₂SO₄.Al₂(SO₄).24H₂O\(\overset{Water}{\rightarrow}\)2K⁺+4\(SO_{4}^{2-}\)+2Al³⁺+24H₂O

Solution

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