List of top Chemistry Questions

What are 'X' and 'Y' respectively in the following reactions? \[ \text{C}_6\text{H}_5\text{CHO} + \text{C}_6\text{H}_5\text{COCH}_3 \xrightarrow{\text{OH}^-,\ 293\text{K}} \text{X} \xrightarrow{\text{NaBH}_4} \text{Y} \]

Arrange the following in increasing order of their boiling points:

The stoichiometric reaction of 516 g of dimethyldichlorosilane with water results in a tetrameric cyclic product X in 75% yield. The weight (in g) of X obtained is___. [Use, molar mass (g mol⁻¹): H = 1, C = 12, O = 16, Si = 28, Cl = 35.5]

50 mL of 0.2 molal urea solution (density = 1.012 g mL⁻¹ at 300 K) is mixed with 250 mL of a solution containing 0.06 g of urea. Both solutions were prepared in the same solvent. The osmotic pressure (in Torr) of the resulting solution at 300 K is ___.
[Use: Molar mass of urea = 60 g mol⁻¹ ; gas constant, R = 62 L Torr K⁻¹ mol⁻¹; Assume, Δ_mixH = 0, Δ_mixV = 0]

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R:
Assertion A: A reaction can have zero activation energy.
Reasons R: The minimum extra amount of energy absorbed by reactant molecules so that their energy becomes equal to threshold value, is called activation energy.
In the light of the above statements, choose the correct answer from the options given below:

Which of the following electron arrangement does not obey Hund’s rule?

At 300 K, one mole of a gas present in a 10 L flask exerted a pressure of 2.706 atm. What is its compressibility factor (Z)?

At T (K), equal weights of H$_2$, D$_2$, and T$_2$ are present in closed vessel. The pressure exerted by this gaseous mixture is P atm. The ratio of partial pressures of T$_2$, D$_2$ and H$_2$ is approximately (H, D and T are isotopes of hydrogen).

The correct order of melting points of Al, Ga, In is:

Match the following

In the given reaction scheme, P is a phenyl alkyl ether, Q is an aromatic compound; R and S are the major products.

The correct statement about S is

The most effective coagulating agent for antimony sulphide sol is:

Identify the correctly matched pairs.

$\mathrm{TiO_2}$ – Pigment industry
$\mathrm{MnO_2}$ – Dry battery cells
$\mathrm{Cu/Ni}$ alloy – UK 'copper' coins

In which of the following pairs the polymer is correctly matched with the forces possessed by them?
A. Neoprene —- Weak intermolecular forces
B. Terylene —- Hydrogen bonding
C. Polystyrene —- Very weak intermolecular forces
D. Polythelene —- Hydrogen bonding

Hypothyroidism is due to
A. High level of iodine in the diet
B. Enlargement of thyroid gland
C. Low levels of iodine in the diet
D. Increased levels of thyroxine

Ortho-sulphobenzimide is used as:

Two statements are given below
Statement I: Chlorobenzene on nitration gives 1-chloro-4-nitrobenzene as major product
Statement II: Chlorobenzene undergoes nitration slowly than benzene
Identify the correct answer

In SN2 reaction, the carbon in the transition state is:

Identify X, Y and Z in the following reactions sequence:

Which of the following produces nitrogen gas after the reaction with nitrous acid?

The number of metalloids in the following elements are: Si, Mn, B, F, Cu, Ag, K, Sb, As, Na, Ge

The correct order of atomic radii of B, Be, N and C is

A gas obeys Charles' law in the temperature range 0--500 K at a given pressure. Its volume changes to zero at temperature of

The standard enthalpy of formation of $CO_2$(g), ${CaO(s)}$ and ${CaCO_3(s)}$ are -393, -634, -1210 kJ mol$^{-1}$ respectively. If all the substans are in standard state, the standard enthalpy of decomposition of calcium carbonate to ${CaO(s)}$ and ${CO_2(g)}$ (in kJ mol$^{-1}$) is