12 Th Papers

Submitted By Aakash19
Words: 1116
Pages: 5

Question 1 ( 1.0 marks)
What is the coordination number of each type of ions in a rock-salt type crystal structure?
Question 2 ( 1.0 marks)
Define the term ‘order of reaction’ for chemical reactions.
Question 3 ( 1.0 marks)
What causes Brownian movement in a colloidal solution?
Question 4 ( 1.0 marks)
In which one of the two structures, and , the bond angle has a higher value? Question 5 ( 1.0 marks)
Write the IUPAC name of the following compound:

Question 6 ( 1.0 marks)
Arrange the following compounds in an increasing order of their acid strengths:
Question 7 ( 1.0 marks)
Write a chemical reaction in which the iodide ion replaces the diazonium group in a diazonium salt.
Question 8 ( 1.0 marks)
Name a substance that can be used as an antiseptic as well as a disinfectant.
Question 9 ( 2.0 marks)
Explain as to why haloarenes are much less reactive than haloalkanes towards nucleophilic substitution reactions.
Which compound in each of the following pairs will react faster in SN2 reaction with −OH? Why?
(i) CH3Br or CH3I
(ii) (CH3)3CCl or CH3Cl
Question 10 ( 2.0 marks)
(a) State the IUPAC name of the following compound:

(b) Complete the following chemical equation:
Question 11 ( 2.0 marks)
State Henry’s law correlating the pressure of a gas and its solubility in a solvent and mention two applications for the law.
Question 12 ( 2.0 marks)
A first order decomposition reaction takes 40 minutes for 30% decomposition. Calculate its value.
Question 13 ( 2.0 marks)
What is meant by the ‘rate constant, k’ of a reaction? If the concentration be expressed in mol L−1 units and time in seconds, what would be the units for k (i) for a zero-order reaction and (ii) for a first-order reaction?
Question 14 ( 2.0 marks)
Define the following terms in relation to proteins:
(i) Peptide linkage
(ii) Denaturation
Question 15 ( 2.0 marks)
List the reactions of glucose which cannot be explained by its open-chain structure.
Question 16 ( 2.0 marks)
Assign a reason for each of the following statements:
(i) Ammonia is a stronger base than phosphine.
(ii) Sulphur in vapour state exhibits a paramagnetic behaviour.
Question 17 ( 2.0 marks)
Draw the structure of the following molecules:
(i) SF4
(ii) XeF4
Question 18 ( 2.0 marks)
What are biodegradable and non-biodegradable detergents? Give one example of each class.
Question 19 ( 3.0 marks)
What is semiconductor? Describe the two main types of semiconductors and explain mechanisms for their conduction.
Question 20 ( 3.0 marks)
Calculate the temperature at which a solution containing 54 g of glucose, (C6H12O6), in 250 g of water will freeze.
(Kf for water = 1.86 K mol−1 kg)
Question 21 ( 3.0 marks)
What are lyophilic and lyophobic sols? Give one example of each type. Which one of these two types of sols is easily coagulated and why?
Question 22 ( 3.0 marks)
State briefly the principles which serve as basis for the following operations in metallurgy:
(i) Froth floatation process
(ii) Zone refining
(iii) Refining by liquation
Question 23 ( 3.0 marks)
Write chemical equations for the following processes:
(i) Chlorine reacts with a hot concentrated solution of sodium hydroxide
(ii) Orthophosphorous acid is heated
(iii) PtF6 and xenon are mixed together
Complete the following chemical equations:
(i) Ca3P2(s) + H2O(l) →……..

(iii) F2(g) + H2O(l) →……..
Question 24 ( 3.0 marks)
(a) What is a ligand? Give an example of a bidentate ligand.
(b) Explain as to how the two complexes of nickel, [Ni(CN)4]2− and Ni(CO)4, have different structures but do not differ in their magnetic behaviour. (Ni = 28)
Question 25 ( 3.0 marks)
Name the reagents which are used in the following conversions:
(i) A primary alcohol to an aldehyde
(ii) Butan-2-one to butan-2-ol
(iii) Phenol to 2, 4, 6-tribromophenol
Question 26 ( 3.0 marks)
Account for the following