List of top Chemistry Questions

The de Broglie wavelength of an electron travelling with 20% of velocity of light is

The correct order of covalent radii of Si, Ge, Sn is:

The first ionization enthalpies of Na, Mg and Si are respectively 496, 737 and 786 kJ mol⁻¹. What would be the first ionization enthalpy of Al in kJ mol⁻¹?

Which of the following is not the property of covalent substances?

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).

If the work done by 2 mol of an ideal gas during isothermal reversible expansion from 5 L to 50 L is -189.1 L atm at constant pressure, the temperature of the gas (in °C) is

At 300 K the enthalpy change for the following reaction is -2800 kJ mol$^{-1}$ \[ C_6H_{12}O_6(s) + 6O_2(g) \rightarrow 6CO_2(g) + 6H_2O(l) \] What is the \(\Delta U\) for the same reaction at 300 K (kJ mol$^{-1}$)?

At T(K), the equilibrium constant for the reaction \( A (g) \rightleftharpoons B (g) \) is \( K_c \). If the reaction takes place in the following form \( 2A(g) \rightleftharpoons 2B(g) \), its equilibrium constant is \( K'_c \). The correct relationship between \( K_c \) and \( K'_c \) is:

Among the following, the correctly matched pair is:

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 number of Faradays required to completely deposit magnesium from 1 L of 0.1 M MgCl\(_2\) aq. solution is:

The most effective coagulating agent for antimony sulphide sol is:

The plot of \( \log \frac{x}{m} \) (y-axis) and \( \log p(x) \) (x-axis) is a straight line inclined at an angle of 45°. When the intercept, \( K \) is 10 and pressure is 0.3 atm, the amount of solute in grams adsorbed per gram of adsorbent (log3 = 0.4771) is:

Arrange the following in order of increasing number of unpaired electrons in them:

1. \([Fe(CN)_6]^{3-}\)
2. \([MnCl_6]^{3-}\)
3. \([FeF_6]^{3-}\)
4. \([Co(NH_3)_6]^{3+}\)

Identify the correctly matched pairs.

1. \(\mathrm{TiO_2}\) – Pigment industry
2. \(\mathrm{MnO_2}\) – Dry battery cells
3. \(\mathrm{Cu/Ni}\) 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

In nucleoside, the base is attached to which position of the sugar molecule?

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: