SAMPLE QUESTION PAPER (2021-22)
CHEMISTRY (043)
TERM II
CLASS 12
Time: 2 Hrs Max. Marks: 35
GENERAL INSTRUCTIONS
1. There are 12 questions in this question paper with internal choice.
2. SECTION – A, Q. No. 1 – 3 are very short answer questions carrying 2 Marks each.
3. SECTION – B, Q. No. 4 – 11 are short answer questions carrying 3 Marks each.
4. SECTION – C, Q. No. 12 is case based question carrying 5 Marks.
5. All questions are compulsory.
6. Use of log tables and Calculator is not allowed.
SECTION A
Attempt all questions: –
Q1. Arrange the following in increasing order of their property indicated (Any two)
(i) Aniline, p-nirtoaniline and p-toluidine (Basic strength)
(ii) C6H5NH2, C6H5NHCH3, C6H5CH2NH2 (Basic strength)
(iii) C6H5NH2, (C2H5)2NH, (C2H5NH2) (Solubility in Water)
Q2. Two half-reactions of an electrochemical cell are given below.
MnO4– (aq) + 8H+ (aq) + 5 e– à Mn2+ (aq) + 4h2O (l); E0 = +1.51 V
Sn2+ (aq) à Sn4+ (aq) + 2 e– ;E0 = -0.15 V
Construct the redox equation from the standard potential of the cell and predict, if the reaction is reactant favoured or product favoured.
Q3. Give reason to support the answer.
(i) Explain, why H2 and O2 do not react at room temperature?
(ii) Write the rate equation for the reaction, A2 + 3B2 à 2C, if the overall order of the reaction is zero.
SECTION B
Q4. Account for the following:
(i) Gabriel phthalimide synthesis is not preferred for synthesising aromatic primary amines.
(ii) tert-butylamine cannot be prepared by the action of NH3 on tert-butyl bromide.
(iii) Acetylation of aniline reduces its activation effect.
OR
Identify A and B in the following reactions:
Q5. (i) Why are low spin tetrahedral complexes not formed?
(ii) What is spectrochemical series? Explain the difference between a weak field ligand and a strong field ligand.
OR
(i) What is lanthanoid contraction? Name an important alloy which contains the lanthanoid metals.
(ii) Calculate the oxidation number of the metals in the following:
(a) [Co (H2O) (CN)(en)2]2+
(b) [CoBr2 (en)2] +
(c) [PtCl4]2-
Q6. Account for the following.
(i) Zn2+ salts are white, while Cu2+ salts are coloured.
(ii) Transition elements show variable oxidation states.
(iii) Sc(21) is a transition element but Ca(20) is not.
Q7. An aromatic compound ‘A’ on heating with Br2 and KOH forms a compound ‘B’ of molecular formula C6H7N, which on reacting with CHCl3 and alcoholic KOH produces a foul smelling compound ‘C’. Write the structure and IUPAC name of compounds A, B and C.
Q8. Observe the figure given below and answer the questions that fillows:
(i) Name the process and apparatus represented in the figure?
(ii) What is the application of this process?
(iii) What happen when this process in colloidal solution is carried out persistently.
Q9. A reaction is of second order with respect to A and first order with respect to B.
(i) Write the differential rate equation.
(ii) How is the rate affected on increasing the concentration of A three times?
(iii) How is the rate affected when the concentration of both A and B is doubled.
OR
(i) A drug becomes ineffective after 30% decomposition. The original concentration was 10 mg mL-1 which become 8.4 mg mL-1 during first 40 months. Assuming the decomposition of first order, calculate the expiry time of the drug in months. What is the half-life of the drug?
(ii) Molecularity of any reaction not be equal to zero?
Q10. Calculate the emf of the following cell at 298 K.
Q11. (i) Transition metals are much harder than the alkali metals. Why?
(ii) Which of the following cations are coloured in aqueous solutions and why?
Sc3+, V3+, Ti4+, Mn2+
[At no. Sc = 21, V = 23, Ti = 22, Mn = 25](iii) Transition metals and their compounds generally exhibit a paramagnetic behaviour
OR
On the basis of the figure given below, answer the following questions
(i) Name the factors on which electrode potential depends.
(ii) The value of E0 across the series are less negative. Why?
(iii) Why E0 value of Ni is more negative and Cu has positive?
SECTION C
Q12. Read the passage given below and answer the following questions:
The compounds containing carbonyl group, i.e., carbon-oxygen double bond are known as carbonyl compounds.
Depending upon the atoms or group of atoms attached on either side of the carbonyl group, carboxyl compounds are divided into three class, i.e., aldehydes, ketones and carboxylic acids.
The carboxyl group is one of the most important functional group in organic chemistry. Aldehydes and ketones can be reduced to a a variety of compounds under different conditions. Aldehydes and ketones are reduced to primary and secondary alcohols respectively by NaBH4 or LiAlH4 as well as catalytic hydrogenation.
Aldehydes differ from ketones in their oxidation reactions. Aldehydes are easily oxidised to carboxylic acids on treatment with different oxidising agent. Even mild oxidising agents mainly Tollen’s reagent and Fehling’s solution also oxidise aldehydes. Ketone cannot be oxidised by weak oxidising agent. Ketones are generally oxidised under vigorous conditions.
(i) Write the product formed by reduction of ketone or aldehyde with HI and red P?
(ii) Write the appropriate reagent that can be used for the following conversion.
(iii)
(iv) Give an example and its IUPAC name of a compound that produces an optically active product on reaction with LIAlH4?
OR
Identify X and write the IUPAC name in the following reaction.
