List of top Chemistry Questions

Identify the correct statements about group 14 elements: 
I. Sn in +2 state is a reducing agent and Pb in +4 state is a strong oxidising agent. 
II. Thermodynamically most stable allotrope of carbon is diamond. 
III. SiCl\(_4\) on hydrolysis gives silicic acid. 
IV. Sn has a higher melting point than Pb.

The hybridization of aluminum in the complexes X and Y respectively is: 

Identify the products formed when zinc reacts with sodium hydroxide solution. Options:
What happens when \( \mathrm{H_2O_2} \) is added to an aqueous solution of ferrous sulphate in an acidic medium?
40 mL of 0.2 M \( \mathrm{CH_3COOH} \) is titrated with 0.2 M NaOH solution. How many mL of NaOH should be added to form a buffer solution with maximum buffer capacity?
At T(K), 3 moles of ethyl alcohol is mixed with 3 moles of acetic acid in a 1L vessel. At equilibrium, 2 moles of ester are formed. Calculate the equilibrium constant for the reaction.
[Ni(H\(_2\)O)\(_4\)]\(^{2+}\) on reaction with ethane-1,2-diamine forms violet color complex. Its formula and magnetic property respectively are

Identify the correct statement from the following: 
UK 'copper' coins are Cu/Ni alloy. AgBr has special light-sensitive properties. Ti\(^{2+}\), V\(^{2+}\), Cr\(^{2+}\) are strong oxidising agents. The magnetic moment of V\(^{2+}\) is 2.84 BM.

Which of the following reactions is not correct with respect to products formed?
The correct statements regarding Hall-Héroult process are:
  • [i.] Steel vessel with lining of carbon acts as anode.
  • [ii.] Purified Al\(_2\)O\(_3\) is mixed with cryolite.
  • [iii.] The overall reaction is \( 2\text{Al}_2\text{O}_3 + 3\text{C} \rightarrow 4\text{Al} + 3\text{CO}_2 \).

The Tyndall effect is observed only when the following conditions are satisfied:

  • (A) The diameter of the dispersed particle is much smaller than the wavelength of the light used.
  • (B) The diameter of the dispersed particle is not much smaller than the wavelength of the light used.
  • (C) The refractive indices of the dispersed phase and the dispersion medium differ greatly in magnitude.
  • (D) The refractive indices of the dispersed phase and the dispersion medium are almost similar in magnitude.
Which of the following is not correct about the adsorption?
A \(\rightarrow\) P is a first-order reaction. At 27°C, the time taken for the completion of 20% of the reaction is \( t_1 \) min. The time taken for the completion of 80% of the reaction is \( t_2 \) min at the same temperature. What is the value of \( \frac{t_2}{t_1} \)?
At 27 °C, the pH of 1 L of aqueous copper sulfate is 5.5. This solution was electrolyzed using two Pt electrodes for some time. What is the pH of remaining copper sulfate solution?
The molar depression constant of water (\(K_f\)) is 1.86 K kg mol\(^{-1}\). What is the approximate \( \Delta H_{fus} \) (in kJ mol\(^{-1}\)) of water if it freezes at 273 K?
At 27 °C, \(x \, g\) of \( \text{CaCl}_2 \) was dissolved in 2.5 L of water. The osmotic pressure of the resultant solution is 0.82 atm. What is \(x\) in grams? (Given \(i = 2.5\), \(R = 0.082 \, \text{L atm mol}^{-1} \text{K}^{-1}\))
Aniline on direct nitration at 288 K gives 51% (A), 47% (B) and 2% (C). ‘B’ on diazotisation, followed by reaction with CuCN | KCN gives a compound X. The percentage of nitrogen in X is:

Identify Z in the following reaction sequence. 


 

What are the reagents X and Y respectively used in the following reaction sequence to convert a nitrile to a methyl group? 


 

Cumene on oxidation in the presence of air gives a compound X. This in the presence of dilute acid gives Y and Z. The total number of \( sp^2 \) carbons in Y and Z is:

What are X, Y and Z in the given reaction sequence?


 

The product of Finkelstein reaction X, is not used in which of the following named reaction?
Which of the following is insoluble in water?

Which of the following represents double stranded helix structure of DNA?

Which of the following molecules is not having glycosidic linkage?