List of top Chemistry Questions

Given below are two statements one is labelled as Assertion A and the other is labelled as Reason R:

Assertion A: The amphoteric nature of water is explained by using Lewis acid/base concept

Reason R: Water acts as an acid with NH3 and as a base with H₂S.

In the light of the above statements choose the correct answer from the options given below:

\(PCl_5\) is well known, but \(NCl_5\) is not. Because,

Metals generally melt at very high temperature. Amongst the following, the metal with the highest melting point will be

The correct order of bond orders of \(C_2^{2-}, N_2^{2-}, O_2^{2-}\) is, respectively

C(s)+O₂(g)→CO₂(g)+400 kJ
C(s)+\(\frac{1}{2}\) O₂(g)→CO(s)+100 kJ
When coal of purity 60% is allowed to burn in presence of insufficient oxygen, 60% of carbon is converted into ‘CO’ and the remaining is converted into ‘CO₂’. The heat generated when 0.6 kg of coal is burnt is _______.

Given below are two statements.
Statement I: The compound

(A) is optically active.
Statement II:

is a mirror image of the above compound A.
In the light of the above statement, choose the most appropriate answer from the options given below.

A compound ‘X’ is a weak acid and it exhibits colour change at pH close to the equivalence point during neutralization of NaOH with CH₃COOH. Compound ‘X’ exists in ionized from in basic medium. The compound ‘X’ is

Octahedral complexes of copper(II) undergo structural distortion (Jahn-Teller). Which one of the given copper(II) complexes will show the maximum structural distortion?
(en – ethylenediamine;H₂N−CH₂−CH₂−NH₂)

In liquation process used for tin (Sn), the metal

Consider the following reaction sequence:

The product ‘B’ is:

Which among the following represents reagent ‘A’?

The Hinsberg reagent is

Correct structure of γ-methylcyclohexane carbaldehyde is

Which of the following 3d-metal ion will give the lowest enthalpy of hydration (Δ_hydH) when dissolved in water?

Given below are the critical temperatures of some of the gases :

Gas	Critical temperature (K)
He	5.2
CH₄	190.0
CO₂	304.2
NH₃	405.5

The gas showing least adsorption on a definite amount of charcoal is

Given below are the quantum numbers for 4 electrons.
A. n=3, l=2, ml=1,m_s=+\(\frac{1}{2}\)
B. n=4, l=1, ml=0,m_s=+\(\frac{1}{2}\)
C. n=4, l=2, ml=–2,m_s=–\(\frac{1}{2}\)
D. n=3, l=1, ml=–1,m_s=+\(\frac{1}{2}\)
The correct order of increasing energy is

Which of the following is not a natural polymer?

Dinitrogen is a robust compound, but reacts at high altitudes to form oxides. The oxide of nitrogen that can damage plant leaves and retard photosyn-thesis is

When borax is heated with CoO on a platinum loop, blue coloured bead formed is largely due to

When ethanol is heated with conc. H₂SO₄, a gas is produced. The compound formed, when this gas is treated with cold dilute aqueous solution of Baeyer’s reagent, is

Which of the following compounds is an example of hypnotic drug?

A compound ‘X’ is acidic and it is soluble in NaOH solution, but insoluble in NaHCO₃ solution. Compound ‘X’ also gives violet colour with neutral FeCl₃ solution. The compound ‘X’ is :

Given below are two statements. One is labelled as Assertion A and the other is labelled as Reason R.
Assertion A : Amylose is insoluble in water.
Reason R : Amylose is a long linear molecule with more than 200 glucose units.
In the light of the above statements, choose the correct answer from the options given below.

Compound ‘A’ undergoes following sequence of reactions to give compound ‘B’. The correct structure and chirality of compound ‘B’ is
[where Et is –C₂H₅]

Portland cement contains ‘X’ to enhance the setting time. What is ‘X’?