List of top Chemistry Questions

When 81.0 g of aluminium is allowed to react with 128.0 g of oxygen gas, the mass of aluminium oxide produced in grams is ----- (nearest integer).

Given below are two statements about X-ray spectra of elements:
Statement (I):A plot of \(\sqrt {v}\) (v=frequency of X-rays emitted) vs atomic mass is a straight line.
Statement (II): A plot of v (v=frequency of X-rays emitted)} vs atomic number is a straight line.

Given below are the atomic numbers of some group 14 elements. The atomic number of the element with the lowest melting point is:

Identify the coordination complexes in which the central metal ion has a \(d^4\) configuration.

Choose the correct answer from the options given below :

When a non-volatile solute is added to the solvent, the vapour pressure of the solvent decreases by 10 mm of Hg. The mole fraction of the solute in the solution is 0.2. What would be the mole fraction of the solvent if the decrease in vapour pressure is 20 mm of Hg?

The alpha-helix and beta-pleated sheet structures of a protein are associated with its:

Standard electrode potentials for a few half-cells are mentioned below:

The standard enthalpy and standard entropy of decomposition of \( N_2O_4 \) to \( NO_2 \) are 55.0 kJ mol\(^{-1}\) and 175.0 J/mol respectively. The standard free energy change for this reaction at 25°C in J mol\(^{-1}\) is (Nearest integer)

Consider the following sequence of reactions to produce major product (A):

The molar mass of the product (A) is g mol−1. (Given molar mass in g mol−1 of C: 12,
H: 1, O: 16, Br: 80, N: 14, P: 31)

During "S" estimation, 160 mg of an organic compound gives 466 mg of barium sulphate. The percentage of Sulphur in the given compound is %.
(Given molar mass in g mol\(^{-1}\) of Ba: 137, S: 32, O: 16)

If 1 mM solution of ethylamine produces pH = 9, then the ionization constant (\(K_b\)) of ethylamine is \(10^{-x}\).

The value of x is (nearest integer).
The degree of ionization of ethylamine can be neglected with respect to unity.

The complex that shows Facial - Meridional isomerism is:

The d-electronic configuration of an octahedral Co(II) complex having a magnetic moment of 3.95 BM is:

Given below are two statements:
Statement I: Fructose does not contain an aldehydic group but still reduces Tollen’s reagent.
Statement II: In the presence of base, fructose undergoes rearrangement to give glucose.
In the light of the above statements, choose the correct answer from the options given below.

In the above diagram, the standard electrode potentials are given in volts (over the arrow). The value of \( E^\circ_{\text{FeO}_4^{2-}/\text{Fe}^{2+}} \) is:

CrCl\(_3\).xNH\(_3\) can exist as a complex. 0.1 molal aqueous solution of this complex shows a depression in freezing point of 0.558°C. Assuming 100\% ionization of this complex and coordination number of Cr is 6, the complex will be:

The element that does not belong to the same period of the remaining elements (modern periodic table) is:

Some CO\(_2\) gas was kept in a sealed container at a pressure of 1 atm and at 273 K. This entire amount of CO\(_2\) gas was later passed through an aqueous solution of Ca(OH)\(_2\). The excess unreacted Ca(OH)\(_2\) was later neutralized with 0.1 M of 40 mL HCl. If the volume of the sealed container of CO\(_2\) was \(x\), then \(x\) is ________________________ cm\(^3\) (nearest integer). [Given: The entire amount of CO\(_2\) reacted with exactly half the initial amount of Ca(OH)\(_2\) present in the aqueous solution.]

From the magnetic behaviour of \([NiCl_4]^{2-}\) (paramagnetic) and [Ni\((CO)_4\)] (diamagnetic), choose the correct geometry and oxidation state.

Arrange the following solutions in order of their increasing boiling points.
(i) \(10^{-4}\) M NaCl
(ii) \(10^{-4}\) M Urea
(iii) \(10^{-3}\) M NaCl
(iv) \(10^{-2}\) M NaCl

In which of the following complexes the CFSE, \(\Delta_0\) will be equal to zero?

Given below are two statements: Statement I: CH\(_3\)-O-CH\(_2\)-Cl will undergo \( S_N1 \) reaction though it is a primary halide.
Statement II: {CH_3-C(-CH_3)(-CH_3)-CH_2-Cl}
will not undergo \( S_N2 \) reaction very easily though it is a primary halide. In the light of the above statements, choose the most appropriate answer from the options given below:

Radius of the first excited state of Helium ion is given as:
\(a_0\) = radius of first stationary state of hydrogen atom.

Match List-I with List-II:

Total number of molecules/species from the following which will be paramagnetic is ________________________. \[ O_2, O_2^+, O_2^-, NO, NO_2, CO, K_2[NiCl_4], [Co(NH_3)_6]Cl_3, K_2[Ni(CN)_4] \]