List of top Chemistry Questions

The unit cell length of sodium chloride crystal is 564 pm. Its density would be:

In RNA, thymine is replaced by__________.

1.5 mol of $O_2$ combine with Mg to form oxide MgO. The mass of Mg (at. mass 24) that has combined is

Electrolysis of dilute aqueous $NaCl$ solution was carried out by passing $10$ milli ampere current. The time required to liberate $0.01$ mol of $H_2$ gas at the cathode is: ($1$ Faraday $=96500Cmo{l}^{-1}$)

The correct order of ionisation enthalpy for Li, Na, Cl, F is:

The letter ?$D$? in $D$-carbohydrates represents

Complexes formed in the cyanide process are:

A solution of colourless unknown salt (X) on boiling with excess of NaOH produces non-flammable gas. The gas evolution ceases after some time. Upon addition of Zn dust to the same solution, the gas evolution restarts. The colourless salt (X) is (are)

The vapour pressure of water at room temperature is 23.8 mm Hg. The vapour pressure of an aqueous solution of sucrose with mole fraction 0.1 is equal to

The longest wavelength in A^o in the Balmer series of singly ionised helium ion, He⁺ is

In which of the following molecules, is the covalent bond most polar ?

Consider the following reaction in aqueous medium at 25^oC.

The equilibrium of above reaction shifts towards left in the presence of

3-tert-butylphenol reacts with different halogens by electrophillic substitution under appropriate conditions that are given below:

The observed pattern of electrophillic substitution can be explained by

Which law directly explains the law of conservation of mass ?

Electrovalent bond formation depends on

The melting point of particles in nano form ___________

Taking chromium and arsenic, which are toxic, out of pressure-treated wood, and using new less toxic chemicals for bleaching paper, are examples of___________.

Solid $Ba{\left({NO}_3\right)}_2$ is gradually dissolved in a $1.0\times {10}^{-4}M{Na}_2{CO}_3$ solution. At which concentration of ${Ba}^{2+}$, precipitate of ${BaCO}_3$ begins to form?$(K_{sp}$ for ${BaCO}_3=5.1\times {10}^{-9})$

When $10ml$ of $0.2M$ solution of an acid is added to $250ml$ of a buffer solution with $pH=6.34$, the $pH$ of the solution becomes $6.32$. The buffer capacity of the solution is:

The tendency of a reaction to take place spontaneously is greatest when the reaction is:

Given the solubility curves of ${\mathrm{KNO}}_3$ and $\mathrm{KCl}$, which of the following statements is not true?

In the presence of a catalyst, the heat evolved or absorbed during the reaction _______.

The pH of a 10 ml aqueous solution of HCl is 4. The amount of water to be added to this solution in order to change its pH from 4 to 5 is:

The enthalpy and entropy change for the reaction:${\mathrm{Br}}_2(l)+{\mathrm{Cl}}_2(\mathrm{g})\to 2\mathrm{BrCl}(\mathrm{g})$ are $30\mathrm{kJ}{\mathrm{mol}}^{-1}$ and $105{\mathrm{JK}}^{-1}{\mathrm{mol}}^{-1}$ respectively.The temperature at which the reaction will be in equilibrium is: