List of top Chemistry Questions

$pH$ of $0.005 M$ calcium acetate $\left( p K_{a}\right.$ of $CH _{3} COOH =4.74$ ) is :

Oxidation number of $Cl$ in $CaOCl _{2}$ (bleaching powder) is :

One mole of a non-ideal gas undergoes a change of state (2.0 atm, 3.0 L. 95 K ) $\rightarrow$ (4.0 atm. 5 0 L, 245 K) with a change in internal energy, $\Delta$E = 30.0L-atm. The change in enthalpy ($\Delta$ H) of the process in L-atm is

Number of lone pairs of electrons on Xe atoms in $XeF_2, XeF_4$ and $XeF_6$ molecules are respectively

Most common oxidation states shown by cerium are

Lucas test is used for the determination of

In the reaction : $ {C6H5CHO + C6H5 NH2 ? C6H5N = HCC6H5 + H2 O,}$ the compound $ {C6H5N = HCC6H5}$ is known as

In an organic compound of molar mass $108 g$ $mol ^{-1} C , H$ and $N$ atoms are present in 9: 1: 3.5 by weight. Molecular formula can be :

Ethers are quite stable towards :

Enzymes with two sites are called

$CH _{3} COCH _{3}$ can be converted to $CH _{3} CH _{2} CH _{3}$ by the action of

Azimuthal quantum number defines

Potassium and caesium are used in photoelectric cells. Potassium and caesium emit electrons on exposure to light.

Physical absorption of molecules takes place on surface only In this process, the bonds of the absorbed molecules are broken.

Phenol is a weaker acid than ethanol. Groups with $+M$ effect and $-I$ effect decrease acidity at $m$-position.

During an adiabatic process, heat energy is not exchanged between system and its surroundings. The temperature of a gas increases when it undergoes an adiabatic expansion.

Diamond is a bad conductor. Graphite is a good conductor.

Cuprous ion $(Cu^+ )$ is colourless whereas cupric ion $(Cu^{++} )$ is blue in the aqueous solution. Cuprous ion $(Cu^+ )$ has unpaired electrons while cupric ion $(Cu^{++} )$ does not.

Absorption spectrum consists of some bright lines separated by dark spaces. Emission spectrum consists of dark lines.

Spectrum of $Li^{2+}$ is similar to that of

The correct order of solubility in water for $He, Ne, Ar, Kr, Xe$ is

If $P$ is pressure and $\rho$ is density of a gas, then $P$ and $\rho$ are related as

The intermediate formed in aldol condensation is

The compound most suitable for the preparation of cyanohydrin is

Absolute values of internal energy of substances can not be determined. It is impossible to determine exact values of constituent energies of the substances.