List of top Chemistry Questions

Why do transition metals form large numbers of complex compounds?

Calculate the ‘spin only’ magnetic moment of a divalent ion of a metal M in aqueous solution. The atomic number of the metal M is 25.

How does acidified potassium permanganate solution react with $Fe^{2+}$ ions? Write ionic equation.

Calculate emf of the given cell: Mg(s) $\mid$ Mg$^{2+}$(0.1 M) $\parallel$ Cu$^{2+}$(1.0 × 10$^{-3}$ M) $\mid$ Cu(s)
Given:
$E^\circ_{\text{Cu}^{2+}/\text{Cu}} = +0.34$ V, \quad $E^\circ_{\text{Mg}^{2+}/\text{Mg}} = -2.37$ V
(log 100 = 2)

State Kohlrausch’s law of independent migration of ions.

Compound A with molecular formula (C₂H₆O) on oxidation by PCC gives compound B, which on treatment with dilute alkali forms compound C (a β-hydroxy aldehyde). B on oxidation by potassium permanganate forms C.
Identify A, B, C and D and write all the chemical equations involved.

How much electricity in terms of Faraday is required to produce 40 g of Al from molten Al$_2$O$_3$? (Given: Atomic mass of Al = 27 u)

Calculate log \(K_c\) for the following reaction at 298 K: Zn(s) + Cu$^{2+}$(aq) $\rightleftharpoons$ Zn$^{2+}$(aq) + Cu(s)
Given:
$E^\circ_{\text{Zn}^{2+}/\text{Zn}} = -0.76 \, \text{V}$, \quad $E^\circ_{\text{Cu}^{2+}/\text{Cu}} = +0.34 \, \text{V}$

The chemistry of the actinoids is more complex as compared to the lanthanoids. Why?

A cell and its emf is given below:
Pt (s) $\mid$ H$_2$(g, 1 bar) $\mid$ H$^+$(aq, 1 M) $\parallel$ Cu$^{2+}$(aq, 1 M) $\mid$ Cu (s)
emf of the cell = +0.34 V
Write the reduction half-reaction at cathode.

How is standard Gibbs energy for a reaction related to equilibrium constant?

Sucrose is dextrorotatory but the mixture obtained after hydrolysis is laevorotatory. Why?

What are reducing sugars?

The boiling point of solution increases when 1 mol of NaCl is added to 1 litre of water while addition of 1 mol of methanol to one litre of water decreases its boiling point. Explain the above observations.

Why is chloroform stored in dark coloured air tight bottles?

Why do tertiary alkyl halides undergo S\textsubscript{N1 reaction at a faster rate?

Define Enantiomers.

Why is chlorobenzene less reactive towards nucleophilic substitution reaction?

Write the major alkene that would be formed by dehydrohalogenation of 2-Bromopentane.

Using valence bond theory, predict: (a) Hybridisation of central metal atom of the complex \([Co(NH_3)_6]^{3+}\)
(b) Its shape and magnetic behaviour
(c) Whether it is a high spin or a low spin complex
[Atomic number: $CO$ = 27]

Give reasons for the following: (a) Reduction with iron scrap and HCl is preferred for the preparation of amines from nitro compounds.
(b) Lower aliphatic amines are soluble in water.
(c) Pyridine is used in the acylation reaction of amines.
(d) Although amino group is o- and p-directing in aromatic electrophilic substitution reactions, aniline on nitration gives a substantial amount of m-nitroaniline.

Why are iron pipes usually coated with zinc?

Define Pseudo first order reaction with an example.