List of top Chemistry Questions

Define the following terms with a suitable example in each case :
(i) Ambidentate ligand
(ii) Double salt

For the compound having molecular formula $\mathrm{C_4H_9Br}$, write :
(a) the isomer which is most reactive towards $\mathrm{S_N1}$ displacement.
(b) the isomer which, on reacting with Na metal in the presence of dry ether, gives 2,5-Dimethylhexane.

Assertion (A): Order of reaction is applicable to elementary as well as complex reactions.
Reason (R): For a complex reaction, molecularity has no meaning.

Assertion (A): Transition metals show their highest oxidation state with oxygen.
Reason (R): The ability of oxygen to form multiple bonds to metals.

Assertion (A): Monobromination of aniline can be conveniently done by protecting the amino group by acetylation.
Reason (R): Acetylation increases the activation effect of the amino group.

Consider the following compounds : Chlorobenzene (I), 2,4,6-trinitrochlorobenzene (II), 2,4-dinitrochlorobenzene (III), 4-nitrochlorobenzene (IV).
The correct order of increasing rate of nucleophilic substitution reactions of these compounds is :

1 mole of liquid A and 2 moles of liquid B make a solution having a total vapour pressure 40 torr. The vapour pressure of pure A and pure B are 30 torr and 45 torr respectively. The above solution :

Assertion (A): Ethers have lower boiling points than the boiling points of alcohols.
Reason (R): This is due to the presence of hydrogen bonding in alcohols.

Which of the following transition metals shows +1 and +2 oxidation states ?

The mole fraction of a solute in 2·0 molal aqueous solution is :

On hydrolysis, which of the following carbohydrates gives only $\mathrm{\beta}$-glucose ?

Which reagent is used to distinguish between primary, secondary and tertiary amines ?

Which of the following product is formed when salicylic acid is treated with $\mathrm{(CH_3CO)_2O}$ in the presence of acid ?

The correct order of decreasing basic strength in aqueous solution of the following is :

On electrolysis of very dilute aqueous solution of NaCl using platinum electrodes :

The oxidation number of Pt in $\mathrm{[Pt(en)_2Cl_2]^{2+}}$ is :

According to Werner's theory, the primary valencies of the central metal atom :

When \(1\ dm^3\) of \(CO_2\) gas is passed over hot coke, the volume of gaseous mixture after complete reaction at STP becomes \(1.4\ dm^3\). The composition of the gaseous mixture at STP is:

Which of the following noble gases is the most reactive and forms the maximum number of compounds?

For the reversible reaction \(\text{N}_2(\text{g}) + 3\text{H}_2(\text{g}) \rightleftharpoons 2\text{NH}_3(\text{g}) + \text{Heat}\), the forward reaction is favored by:

The standard electrode potentials for \(\text{Zn}^{2+}/\text{Zn}\), \(\text{Ni}^{2+}/\text{Ni}\), and \(\text{Fe}^{2+}/\text{Fe}\) are \(-0.76\text{ V}\), \(-0.23\text{ V}\), and \(-0.44\text{ V}\) respectively. Which of the following reactions is spontaneous?

According to VSEPR theory, which of the following species has a see-saw shape?

When phenol is treated with chloroform and aqueous sodium hydroxide, the major product formed is:

On hydrolysis, which of the following carbohydrates gives only β-glucose ?

Consider the following compounds : Chlorobenzene (I), 2,4,6-trinitrochlorobenzene (II), 2,4-dinitrochlorobenzene (III), 4-nitrochlorobenzene (IV). The correct order of increasing ease of nucleophilic substitution reactions of these compounds is :