List of top Chemistry Questions asked in JEE Main

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.]

Using very little soap while washing clothes, does not serve the purpose of cleaning of clothes, because:

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

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:

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

Assertion A: Polluted water may have a value of BOD of the order of 17 ppm.

Reason R: BOD is a measure of oxygen required to oxidise both the bio-degradable and non-biodegradable organic material in water.

In the light of the above statements, choose the most appropriate answer from the options given below.

Which one of the following compounds is used as a chemical in certain type of fire extinguishers?

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

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

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

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

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

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

Consider the reaction
\(4\text{HNO}_3(\text{l}) + 3\text{KCl}(\text{s}) \rightarrow \text{Cl}_2(\text{g}) + \text{NOCl}(\text{g}) + 2\text{H}_2\text{O}(\text{g}) + 3\text{KNO}_3(\text{s})\)
The amount of HNO₃ required to produce 110.0 g of KNO₃ is
(Given : Atomic masses of H, O, N and K are 1, 16, 14 and 39 respectively.)

200 mL of 0.01 M HCl is mixed with 400 mL of 0.01 M H₂SO₄. The pH of the mixture is ___.
[Given log 2 = 0.30, log 3 = 0. 48, log 5 = 0.70, log7 = 0.84, log 11 = 1.04.]

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: 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.

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 :

Which among the following represents reagent ‘A’?