List of top Chemistry Questions

The number of bridged oxygen atoms present in compound B formed from the following reactions is

\(PB(NO_3)^2→(673 K)→A+PBO+O_2A→(Dimerise)B.\)

Which one of the following is an example of artificial sweetner?

Solute A associates in water. When 0.7 g of solute A is dissolved in 42.0 gof water, it depresses the freezing point by 0.2°C. The percentage association of solute A in water is :

[Given : Molar mass of A = 93 g mol^–1. Molal depression constant of water is 1.86 K kg mol^–1.]

The energy of one mole of photons of radiation of wavelength \(300\) \(nm\) is (Given \(h\) = \(6.63 × 10^{–34}\)Js, \(N_A\) = \(6.02 × 10^{23}\) \(mol^{–1}\), \(c = 3 × 10^8\) \(ms^{–1}\))

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:

Choose the correct answer :

1. The minimum energy that must be possessed by photons in order to produce the photoelectric effect with platinum metal is

[Given The threshold frequency of platinum is 1.3 × 10¹⁵ s^–1 and h = 6.6 × 10^–34 Js.]

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

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

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

Which of the following is not a natural polymer?

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

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.

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.

Correct structure of γ-methylcyclohexane carbaldehyde 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 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

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)

Given below are two statements.
Statement-I: Stannane is an example of a molecular hydride.
Statement-II: Stannane is a planar molecule
In the light of the above statement, choose the most appropriate answer from the options given below.

Which among the following represents reagent ‘A’?

Consider the following reaction sequence:

The product ‘B’ is:

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

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 _______.

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