List of top Chemistry Questions

The protecting power of lyophilic colloidal sol is expressed in terms of

Ammonia undergoes self-dissociation according to the reaction, $2 NH _{3}(l) \rightleftharpoons NH _{4}^{+}{ }_{(a m)}^{+}+ NH _{2(a m)}^{-}$ where am, stands for ammoniated. When $1$ mole of $NH _{4} Cl$ is dissolved in $1\, kg$ of liquid ammonia, the b. p. at $760$ tour is observed at $-32^{\circ} C$ (Normal b.p. of $N H_{3(l)}$ is $-33.4^{\circ} C$ ). What conclusions are reached about the nature of the solution?

Standard enthalpy of vapourisation $\Delta_{\text {vap }} H ^{\Theta}$ for water at $100^{\circ} C$ is $40.66\, kJ\, mol ^{-1}$. The internal energy of vaporisation of water at $100^{\circ} C$ (in $kJmol ^{-1}$) is : (Assume water vapour to behave like an ideal gas)

Which one of the following statements regarding photochemical smog is not correct?

Limiting molar conductivity of $NH_4OH $ $[i.e. \,\wedge^\circ {m (NH_4OH)}]$ is equal to

Consider two half-cells based on the reaction $A g^{+}(a q)+e^{-} \rightarrow A g(s)$ The left half-cell contains $A g^{+}$ions at unit concentration, and the right half-cell initially had the same concentration of $A g^{+}$ions, but just enough $NaCl_{(a q)}$ had been added to completely precipitate the $A g_{(a q)}^{+}$as $AgCl$. If the emf of the cell is $0.29\, V$, the $\log _{10} K_{s p}$ would have been

When $Cl_2$ gas reacts with hot and concentrated sodium hydroxide solution, the oxidation number of chlorine changes from

Aluminium is extracted from alumina $(Al_2O_3)$ by electrolysis of a molten mixture of

100 mL of N/5 HCl was added to 1 g of pure $ {CaCO_3}$ What would remain after the reaction?

The ratio of number of oxygen atoms (O) in 16.0 g ozone $(O_3), \,28.0\, g$ carbon monoxide $(CO)$ and $16.0$ oxygen $(O_2)$ is (Atomic mass: $C = 12,0 = 16$ and Avogadro?? constant $N_A = 6.0 x 10^{23}\, mol^{-1}$)

Which of the statements is not true?

A metal crystallizes with a face-centered cubic lattice. The edge of the unit cell is $408\, pm$. The diameter of the metal atom is

A certain gas takes three times as long to effuse out as helium. Its molecular mass will be:

A nucleophilic substitution reaction proceeds through $S _{ N } 1$ mechanism. So, the reaction is

Dimension of universal gas constant $(R)$ is

The product of reaction between aniline and acetic anhydride is

The correct order of electron gain enthalpy $ (\Delta _{eg}H) $ of the halogen atoms is

The $ C-H $ bond distance is the longest in

$50\, mL$ of each gas A and of gas B takes $150$ and $200\, s$ respectively for effusing through a pin hole under the similar conditions. If molecular mass of gas B is $36,$ the molecular mass of gas A will be

The element with positive electron gain enthalpy is

One mole of propanone and one mole of formaldehyde are the products of ozonolysis of one mole of an alkene. The alkene may be

The dissolution of a gas in a liquid is governed by

$2$ -bromobutane reacts with $OH ^{-}$ in $H _{2} O$ to give $2$ -butanol. The reaction involves

Glucose can be converted into ethyl alcohol using

The rate of reactions exhibiting negative activation energy