List of top Chemistry Questions asked in JEE Main

Given below are two statements:
Statement I: If BOD value is 4 ppm and dissolved oxygen is 8 ppm, it is a good quality water.
Statement II: If the concentration of zinc and nitrate is 5 ppm, then it can be used as good quality water.

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R:
Assertion A: In the photoelectric effect electrons are ejected from the metal surface as soon as the beam of light of frequency greater than threshold frequency strikes the surface.
Reason R: When the photon of any energy strikes an electron in the atom transfer of energy from the photon to the electron takes place.

The complex that dissolves in water is:

A mixture of 1 mole of H₂O and 1 mole of CO is taken in a 10 liter container and heated to 725 K. At equilibrium, 10 M of water by mass reacts with carbon monoxide according to the equation: \[ CO(g) + H_2O(g) \rightleftharpoons CO_2(g) + H_2(g) \] The equilibrium constant \( K_c \times 10^7 \) for the reaction is ______

An atomic substance A of molar mass 12 g mol$^{-1}$ has a cubic crystal structure with edge length of 300 pm. The no. of atoms present in one unit cell of A is _____ (Nearest integer)

The ratio of spin-only magnetic moment values \( \mu_{\text{eff}}[Cr(CN)_6]^{3-}/\mu_{\text{eff}}[Cr(H_2O)_6]^{3+} \) is_____

A solution of sugar is obtained by mixing 200g of its 25% solution and 500g of its 40% solution (both by mass). The mass percentage of the resulting sugar solution is ______ (Nearest integer)

0.004 M K₂SO₄ solution is isotonic with 0.01 M glucose solution. Percentage dissociation of K₂SO₄ is______ (Nearest integer)

The number of hyperconjugation structures involved to stabilize carbocation formed in the below reaction is _______

The above reaction was studied at 300 K by monitoring the concentration of FeSO₄, in which initial concentration was 10 M and after half an hour became 8.8 M. The rate of production of Fe₂(SO₄)₃ is _____ × 10⁻⁶ mol L⁻¹ s⁻¹

25 mL of silver nitrate solution (1M) is added dropwise to 25 mL of potassium iodide (1.05 M) solution. The ions(s) present in very small quantity in the solution is/are:

When a solution of mixture having two inorganic salts was treated with freshly prepared ferrous sulphate in acidic medium, a dark brown ferric ion was formed when treated with ferric chloride. It gave deep red colour which disappeared on boiling and a brown red ppt was formed. The mixture contains:

The polymer X consists of linear molecules and is closely packed. It is prepared in the presence of triethylaluminium and titanium tetrachloride under low pressure. The polymer X is:

The value of x compound ‘D’ is

Three organic compounds A, B and C were allowed to run in thin layer chromatography using hexane and gave the following result (see figure). The R_f value of the most polar compound is ____ x 10^-2.

The reaction 2NO + Br2 → 2NOBr 
takes places through the mechanism given below : 
NO + Br2 ⇔ NOBr2 (fast)  
NOBr2 + NO → 2NOBr (slow) 
The overall order of the reaction is_____.

pH of 1 litre of HCL solution is 1. How much water (in litres) is added to make pH=2?

Match the terms in Column-I with their description in Column-II and choose the correct option:

	Column I		Column II
(A).	Biodegradable	(P).	Polyacrylonitrie
(B).	Synthetic	(Q).	PHBV
(C).	Natural	(R).	Dacron
(D).	Polyester	(S).	Rubber

The incorrect statement regarding the reaction given below is

The major products ‘P’ formed in the following sequence of reaction is

In the following reaction

A is

Products The two products formed in above reaction are

Correct statements for the given reaction are:

A. Compound 'B' is aromatic 
B. The completion of above reaction is very slow 
C. 'A' shows tautomerism 
D. The bond lengths C-C in compound B are found to be same 
Choose the correct answer from the options given below:

Match List-I with List-II

	List-I		List-II
A	Nitrogen oxides in air	I	Eutrophication
B	Methane in air	II	pH of rain water becomes 5.6
C	Carbon dioxide	III	Global warming
D	Phosphate fertilisers in water	IV	Acid rain

Choose the correct answer from the options given below: