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:
(CH3)2CHCOOH, CH3CH2CH(Br)COOH, CH3CH(Br)CH2COOH
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.
Questions
Question 9 ( 2.0 marks)
Explain as to why haloarenes are much less reactive than haloalkanes towards nucleophilic substitution reactions.
OR
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:
CH3CH2CH=CH2 + HBr
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.
Questions
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
OR
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…