List of top Chemistry Questions

On treatment of $100\, mL$ of $0.1\, M$ solution of $CoCl _{3} \cdot 6 H _{2} O$ with excess $AgNO _{3} ; 1.2 \times 10^{22}$ ions are precipitated. The complex is

When the heat of reaction at constant pressure is \(-5 \times 10^3\) cal and the entropy change is \(7.4 \, \text{cal} \, \text{deg}^{-1}\) at \(25^\circ\text{C}\), the reaction is predicted as

Predict the correct intermediate and product in the following reaction :
$H_{3}C-C\equiv CH\underset{HgS{O}_4}{\overset{H_{2}O,H_{2}S{O}_4}{\to }}\underset{\text{(A)}}{\mathrm{Intermediate}}\to \underset{\text{(B)}}{\mathrm{product}}$

The e.m.f. of a Daniell cell at $298\, K$ is $E _{1}$. $Zn / SO _{4}(0.01 M ) \| CuSO _{4}(1.0 M ) / Cu$ When the concentration of $ZnSO _{4}$ is $1.0\, M$ and that of $CuSO _{4}$ is $0.01\, M$, the e.m.f. is changed to $E _{2}$. What is the relationship between $E _{1}$ and $E _{2}$ :

A metal crystallises in a face centred cubic structure. If the edge length of its unit cell is $'a'$, the closest approach between two atoms in metallic crystal will be :

The rate of a reaction quadruples when the temperature changes from $300$ to $310\, K$. The activation energy of this reaction is : (Assume activation energy and pre-exponential factor are independent of temperature; $ln\, 2 = 0.693; R=8.314 \,J$ $mol^{-1} \, K^{-1}$)

The Tyndall effect is observed only when following conditions are satisfied (a) The diameter of the dispersed particles is much smaller than the wavelength of the light used. (b) The diameter of the dispersed particle is not much smaller than the wavelength of the light used (c) The refractive indices of the dispersed phase and dispersion medium are almost similar in magnitude (d) The refractive indices of the dispersed phase and dispersion medium differ greatly in magnitude

The number of $S=O$ and $S-OH$ bonds present in peroxodisulphuric acid and pyrosulphuric acid respectively are :

Consider the following reaction,

X is

The volume of water to be added to 100 cm³ of 0.5 N H₂SO₄ to get decinormal concentration i

In which of the following the oxidation number of oxygen has been arranged in increasing order ?

Which of the following region is coldest ?

Which of the following fibres is made of polyamides ?

Aqueous 10% NaHCO₃ solution is used as a reagent for identifying 'A'. Which of the following compounds yield 'A' on hydrolysis ?

Sulphur reacts with chlorine in 1 : 2 ratio and forms X. Hydrolysis of X gives a sulphur compound Y. The hybridization of central atom in the anion Y is

Flux is used to

A first order reaction is 50% completed in 1.26 × 10¹⁴ How much time would it takes for 100% completion ?

A solid AB has NaCl structure. If the radius of cation A⁺ is 170 pm, then the maximum possible radius of the anion B^- is

The electrons identified by quantum numbers n and l, are as follows
(I) n = 4, l = 1
(II) n = 4, l = 0
(III) n = 3, l = 2
(IV) n = 3, l = 1
If we arrange them in order of increasing energy, i.e. from lowest to highest, the correct order is

Match the type of series given in Column I with the wavelength range given in Column II and choose the correct option.

Column I		Column II
A.	Lyman	1.	Ultraviolet
B.	Paschen	2.	Near infrared
C.	Balmer	3.	Far infrared
D.	Pfund	4.	Visible

In the cyanide extraction process of silver from argentite ore, the oxidizing and reducing agents are respectively:

The standard reduction potential for Zn²⁺/Zn, Ni²⁺/Ni and Fe²⁺/Fe are -76, -0.23 and -0.44 V, respectively.
The reaction X + Y²⁺ → X²⁺ + Y will be spontaneous when

The product of acid hydrolysis of (P) and (Q) can be distinguished by

Clemmensen reaction of ketone is carried out in the presence of:

The main product formed in the following reaction is