List of top Chemistry Questions asked in JEE Main

In which of the following pairs of elements electron gain enthalpy difference is highest?

A binary compound has Y-atoms forming FCC unit cell and another type of X-atoms occupying \(\frac{1}{3}\)rd of tetrahedral voids. Find out the molecular formula of the compound

 

The value of \(log_{10}K\) for a reaction A ⇋ B is

(Given,

 \(\Delta H^{\circ}_{298K}\) = –54.67 kJ \(mol^{-1}\)

 \(\Delta H^{\circ}_{298K}\) = 10 kJ \(mol^{-1}\)

 and R = 8.314 J \(K^{-1}mol^{-1}\)

 2.303 × 8.314 × 298 = 5705) 

Determine the amount of urea (NH2CONH2) to be added in 1000 g of water to decrease its vapour pressure by 25%. 

Which of the following slows down the process of setting of the cement? 

Number of ambidentate ligands in given complex [M(en)(SCN)4]:

2[Au(CN)2]– + Zn \(\to\) [Zn(CN)4]2– + 2Au\(\downarrow\) is which of these 
(A) Redox reaction 
(B) Displacement reaction
(C) Combination reaction
(D) Decomposition reaction 

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
A ⇒ Spin only magnetic moment of [Fe(CN)6]–3 is 1.73 B.M. and [Fe(H2O)6]+3 is 5.92 B.M.
R ⇒ In both cases Fe have +3 oxidation state
In the light of the above statements, write the detailed answer:
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : Radius of H+ is 1.5 × 10–3 pm
Reason (R) : H+ cannot exist independently
In the light of the above statements, write the detailed answer:

Oxidation number of Mo in Ammonophosphomolybdate

Which of following are reducing and oxidising agent respectively.

Match the terms in Column-I with their description in Column-II:
Column-I Column-II
PN2O5 (i)N–N bond
QN2O(ii)N–O–N bond
RN2O4 (iii)N=N / N≡N bond
SNO2(iv)N=O bond

Choose the correct option.

Match the terms in Column-I with their description in Column-II and choose the correct option :
Column IColumn II
(i)Vitamin AaBeri-beri
(ii)Vitamin C (Ascorbic acid)bCheilosis
(iii)RiboflavincXerophthalmia
(iv)ThiaminedScurvy

Photochemical smog found mainly in 

Match the terms in Column-I with their description in Column-II and choose the correct option:
Column I (Chemical reactions)Column II (Enzymes used)
(i)Glucose → CO2 + EthanolaPepsin
(ii)Sucrose→Glucose + Fructose bDiastase
(iii)Starch →Maltose cZymase
(iv)Protein→Amino acids dInvertase

How many bromo products are formed when ethane is reacted with excess of Br2 on heating?

Match the following with the correct name of reaction

ReactionName of reaction
(I)
(P)Gattermann Koch reaction
(II)
(Q)Hell Volhard Zelinsky
(III)
(R)Iodoform reaction

Product (P) and (Q) are respectively
'$A$' in the given reaction is
Which of the following is not ambidentate ligand
The ratio of spin-only magnetic moment values \( \mu_{\text{eff}}[Cr(CN)_6]^{3-}/\mu_{\text{eff}}[Cr(H_2O)_6]^{3+} \) is_____
Element not present in Nessler’s reagent is

In which form does \(BeCl_{2}\) exist in the solid state, vapor state and high temperature?
(1) Polymeric, Dimeric, Monomeric
(2) Dimeric, Polymeric, Monomeric
(3) Monomeric, Dimeric, Polymeric
(4) Polymeric, Monomeric, Dimeric

Which one of the following elements will remain as liquid inside pure boiling water?