Chemistry Question Bank

Gº vs T plot in the Ellingham’s diagram slopes downwards for the reaction. (RPMT 2006) (a) Mg⁺ O MgO → (b) 2Ag⁺ O Ag O → (c) C O CO → (d) CO O CO →

Sulphide ores of metals are usually concentrated by Froth floatation process. Which one of the following sulphide ores offers an exception and is concentrated by chemical leaching? (AIPMT 2007)

Blister copper is: (AIPMT 2007)

Which of the following statements, about the advantage of roasting of sulphide ore before reduction is not true? (RPMT 2007)

Which metal has a greater tendency to form metal oxide? (RPMT 2008)

In the extraction of silver, Ag₂S is dissolved in: (AIPMT 2009)

The process of extracting Ti from TiCl₄ in presence of Mg is called: (RPMT 2009)

In the cryolite CaCl₂ is added to: (AIPMT 2009)

The minimum voltage required to electrolyse alumina in the Hall-Heroult process is (Given, o f G Al O 1520kJ mol ; o f G CO 394kJmol ) (AIIMS 2009)

Which of the following diagram explain extraction of metal from metal oxide: (RPMT 2010)

The solution of strong acid and weak base (FeCl₃) is

Aq. solution of sodium cyanide is

Ka for HF is 3.5 × 10–4. Calculate Kb for the fluoride ion.

HCN is  a weak  acid (Ka =  6.2 ×  10–10).  NH₄OH  is a weak base (Kb = 1.8 × 10–5). A 1M solution of NH₄CN would be :

A physician wishes to prepare a buffer solution at pH = 3.58 that efficiently resists a change in pH yet contains only small conc. of the buffering agents. Which one of the following weak acid together with its sodium…

The  pH  of  blood  does  not  appreciably  change  by  a small addition of acid or a base because blood

How many moles of HCOONa must be added to 1L of 0.1 M HCOOH to prepare a buffer solution with a pH of  3.4  ?  (Given  :  Ka  for  HCOOH  =  2  ×  10 –4); (10-0.3 = 0.5)

The dissociation constant of HCN is 5 × 10 –10. The pH of the solution prepared by mixing 1.5 mole of HCN and  0.15  moles  of  KCN  in  water  and  making  up the total volume to 0.5 dm 3 is

In  a  mixture  of  a  weak  acid  and  its  salt, the  ratio  of concentration of acid to salt is increased ten-fold. The pH of the solution

The  pKa  value  of  NH₃  is  5.  Calculate  the  pH  of  the buffer solution, 1 L of which contains 0.01 M NH₄Cl and 0.10 M NH₄OH

Consider the following solutions of equal concentrations. A = NH₄Cl        B = CH₃COONa C = NH₄OH      D = CH₃COOH A  buffer  solution  can  be  obtained  by  mixing  equal volumes of

Which of the following pairs constitutes a buffer?

Solution  of  0.1  N  NH₄OH  and  0.1  N  NH₄Cl  has  pH 9.25. The pKb of NH₄OH is

One litre of a buffer solution containing 0.01 M NH₄Cl and 0.1 M NH₄OH having pKb of 5 has pH of

A buffer solution of pH 9 can be prepared by mixing