The role of calcination in metallurgical operations is

to remove moisture
to decompose carbonates
to drive off organic matter
to decompose carbonates and drive off moisture and organic matter

Solution

On mixing ethyl acetate with aqueous sodium chloride, the composition of the resultant solution is

CH₃COCl+ C₂H₅OH + NaOH
CH₃COONa + C₂H₅OH
CH₃COOC₂H₅ + NaCl
CH₃Cl + C₂H₅COONa

Solution

There is no reaction hence the resultant mixture contains CH₃ COOC₂H₅+ NaCl

Which of the following represents correct set of the four quantum numbers for an electron in a 4d subshell ?

4, 2, 1, 0
4, 2, 1, –1/2
4, 3, 2, +1/2
4, 3, –2, –1/2

Solution

The mass of a molecule of water is

3× 10^–25kg
3× 10^–26kg
1.5 × 10^–26kg
2.5 × 10^–26kg

Solution

Mass of one molecule of Water
= \(\frac{18}{6.023 \times 10^{23}}\)
=3 × 10^-23g = 3 × 10^-26kg

The combination of three 2p orbitals of one atom and three 2p orbitals of another atom can give rise to :

three molecular orbitals
six (π 2p) molecular orbitals
four (π 2p) and two(σ 2p) molecular orbitals
two molecular orbital which are symmetrical around the bond axis

Solution

Three 2p orbitals of one atom and three 2p orbitals of another atom give rise to four(π 2p) and two (σ 2p) molecular orbitals.

Among 2p_x, 2p_y and 2p_z orbitals of two atoms 2p_z combines with 2p_z along z-aixs give rise to two π 2p molecular orbitals, while 2p_x combines with 2p_x and 2p_y combines with 2p_y give rise to two π 2p_x and two σ 2p_y molecular orbitals.

Nitrobenzene is reduced to azoxybenzene using

Sn/HCl
Zn/NH₄Cl
As₂O₃/NaOH
Zn/NaOH

Solution

If xis amount of adsorbate and m is amount of adsorbent,which of the following relations is not related to adsorption process ?

x/ m= f (p) at constant T.
x/ m= f(T) at constant p.
p = f(T) at constant (x / m)
x/m =p´T

Lanthanum is grouped with f-block elements because

it has partially filled f-orbitals
it is just before Ce in the periodic table
it has both partially filled f and d-orbitals
properties of lanthanum are very similar to the elements of f-block

Identify the incorrect statement among the following:

4f and 5f orbitals are equally shielded.
d-Block elements show irregular and erratic chemical properties among themselves.
La and Lu have partially filled d-orbitals and no other partially filled orbitals.
The chemistry of various lanthanoids is very similar.

Solution

4f orbital is nearer to nucleus as compared to 5f orbital therefore, shielding of 4 f is more than 5f.

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

Statement-1 :Acetic acid does not undergo haloform reaction.

Statement-2 :Acetic acid has no alpha hydrogens.

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

What are the starting materials to get 2-methylpropene as the major product ?

Sodium methoxide and sec-butyl bromide.
Sodium ethoxide and sec-butyl bromide.
Sodium tert-butoxide and ethyl bromide.
Sodium methoxide and tert-butyl bromide

Solution

The melting point of lithium (181°C) is just double the melting point of sodium (98°C) because –

down the group, the hydration energy decreases
down the group, the ionization energy decreases
down the group the cohesive energy decreases
None of these

Solution

The atom becomes larger on descending the group, so the bonds becomes weaker (metallic bond), the cohesive force/energy decreases and accordingly melting point also decreases.

Acetanilide on nitration followed by alkaline hydrolysis mainly gives –

o-Nitroaniline
p-Nitroaniline
m-Nitroaniline
2, 4, 6-Trinitroaniline

Solution

Dehydration of alcohol is an example of

Redox reaction
Elimination reaction
Substitution reaction
Addition reaction

Solution

The molecular weight of O₂ and SO₂ are 32 and 64 respectively. At 15°C and 150 mm Hg pressure, one litre of O₂ contains ‘N’ molecules. The number of molecules in two litres of SO₂ under the same conditions of temperature and pressure will be:

Solution

According to Avogadro's law "equal volumes of all gases contain equal number of molecules under similar conditions of temperature and pressure".

Thus if 1 L of one gas contains N molecules, 2 L of any other gas under the same conditions of temperature and pressure will contain 2N molecules.

Which of the following substances acts as an oxidising as well as a reducing agent?

Na₂O
SnCl₂
Na₂O₂
NaNO₂

Solution

In Na₂O, SnCl₂ and Na₂O₂ central atom is either in lowest or highest oxidation state, so it can function either as an oxidising or a reducing agent but not both.However, the oxidation state of N in NaNO₂ is +3 which lies between its highest(+5) and lowest (–3) values.

For advertisement, the coloured discharge tubes contain :

A mixture of components A and B will show –ve deviation when

ΔV_mix > 0
ΔH_mix < 0
A–B interaction is weaker than A–A and B–B interactions
A–B interaction is stronger than A–A and B–B interactions

Solution

A solution containing A and B components shows negative deviation when A–A and B–B interactions are weaker than that of A–B interactions. For such solutions.ΔH = –ve and ΔV = –ve.

The oxide of lead used in lead accumulators is :

PbO
Pb₂O₃
Pb₃O₄
PbO₂

Solution

PbO₂ is a strong oxidising agent and is produced in situ in lead storage batteries. The anode is oxidized to PbO₂ and cathode is reduced to spongy Pb.

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