Roll No. Name Class & Section

CATION S

APEEJAY COMMONANNUAL EXAMINATION, 2019-20 CHEMISTRY

Time Allowed: 3.00 Hrs.

Class - XI

Maximum Marks: 70

General Instructions:

1. This question paper contains 37 Questions.

(b) All questions are compulsory.

1. Section A contains 20 questions of one mark,

Section B contains 7 questions of two marks,

Section C contains 7 questions of three marks,

Section D contains 3 questions of five marks each.

1. Section A comprises of MCQs, Assertion-Reason Questions and Very Short Answer Questions. These questions are to be answered in one word, one sentence or as per the exact requirement of the question.
2. There is no overall choice. However, an internal choice has been provided in 2 questions of one mark, 2 questions of two marks, 4 questions of three marks and all the 3 questions of five marks.
3. Use of calculators is not permitted. You may use logarithmic tables if required.

Section-A.

Read the given passage and answer the questions 1 to 5 that follow:

The periodic table houses a few families and group of elements, each having its own particular properties. Early p-block comprises of group 13 and 14. Group 13 consists of B, Al, Ga, In, Tl with general configuration ns²np¹. Group 14 is Carbon family and comprises of C, Si, Ge, Sn, Pb with general configuration ns²np². Boron and carbon family form versatile compounds. Boric acid is used as an antiseptic for eyes whereas zeolites are shape selective catalysts. R/8 [.P.T.O.]

1. What happens when boric acid is heated above 370K? 1
2. Name a zeolite which is used to convert alcohols directly into gasoline. 1
3. Draw the structure of Diborane. 1

1. What happens when diborane reacts with ammonia?
2. Why is PbCl₂ more stable than PbCl₄? Questions 6 to 10 are one word answers:
3. 1 litre of a gas weighs 1.964 g at STP. What is its molecular mass?
4. Amongst ClF₃ or BCl₃, which molecule has bond angle 120°.

OR

Based on VSEPR theory, total number of 90° bond angles present in the molecule of SF4 are ......

1. The Vander waal's constant 'a' for different gases are given below:

Gas a (atm L-2 mol-2.) <math>O_2</math> 1.36 N2 · 1.39 CH₄ 2.25 <math>NH_3</math> 4.17

Which gas can be most easily liquified? 9.

Water is a liquid whereas H2S is a gas. Give reason.

1. Algae reduce dissoved oxygen in water. This process is called ...... Questions 11 to 15 are multiple choice questions:
2. Which of the following pairs of d orbitals have electron density along the axis? 1

1. <math>d_{z^2}</math>, <math>d_{xz}</math>

1. d_z2, d_x2-y2,

(b) d_yz, d_xz(d) d_zy, d_x²-y²

1. In second period of periodic table, first ionization enthalpy follows the order. 1

1. Ne > F > O > N > C > Be > B > Li
2. Ne>F>N>C>O>Be>B>Li

R-8/Chemistry/XI [2]