List of top Chemistry Questions

Portland cement contains ‘X’ to enhance the setting time. What is ‘X’?
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
Which of the following is not a natural polymer?

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’?

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

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 _______.

The reaction of zinc with excess of aqueous alkali, evolves hydrogen gas and gives:
Consider, \(PF_5,BrF_5,PCl_3,SF_6,[ICl_4]^–,ClF_3 and\ IF_5\).
Amongst the above molecule(s)/ion(s), the number of molecule(s)/ion(s) having \(sp^3d^2\) hybridisation is _____.
A 10 g mixture of hydrogen and helium is contained in a vessel of capacity 0.0125 m3 at 6 bar and 27°C. The mass of helium in the mixture is _______ g. (nearest integer)
Given : R = 8.3 J K–1 mol–1
(Atomic masses of H and He are 1 u and 4 u, respectively)
For a cell, \(Cu(s)|Cu^{2+}(0.001M)||Ag^+(0.01M)|Ag(s)\)
the cell potential is found to be \(0.43 V\) at \(298 K\). The magnitude of standard electrode potential for \(Cu^{2+}/{Cu}\) is ____ \(× 10^{–2}\) V.
[Given: \(E_{Ag^+/Ag^⊖}=0.80\) V and \(\frac {2.303RT}{F}=0.06 V\)]
In a linear tetrapeptide (constituted with different amino acids) – (number of peptide bonds) is _____.
Consider the following sulphur based oxoacids.
\(H_2SO_3,H_2SO_4,H_2S_2O_8 \)and \(H_2S_2O_7\)
Amongst these oxoacids, the number of those with peroxo (O–O) bonds is_____.
Number of lone pairs of electrons in the central atom of SCl2, O3, CIF3 and SF6, respectively, are:
The reaction between X and Y is first order with respect to X and zero order with respect to Y.
reaction between X and Y is first order with respect to X and zero order with respect to Y.
Examine the data of table and calculate ratio of numerical values of M and L. (Nearest integer)
The number of stereoisomers formed in a reaction of (±) Ph (C = O) C (OH) (CN) Ph with HCN is_____.
[Where, Ph is – C6H5]
The number of chlorine atoms in bithionol is ______ .
Lithium nitrate and sodium nitrate, when heated separately, respectively, give :
Which among the following pairs of the structures will give different products onozonolysis? (Consider the double bonds in the structures are rigid and not delocalized)

Consider the above reaction, the compound ‘A’ is :

Fig.
Which among the following is the strongest Bronsted base?
[Fe(CN)6]3– should be an inner orbital complex. Ignoring the pairing energy, the value of crystal field stabilization energy for this complex is (–) _____ Δ0. (Nearest integer)
Which among the following pairs has only herbicides?