Series JSK/2- Set 4

CBSE Board

Class X Science

Board Paper

Term 1 - 2021

Time: 90 minutes

Total Marks: 50

General Instructions:

This question paper contains 60 questions out of which 50 questions are to be attempted.

All questions carry equal marks.

The Question Paper consists of three sections- Section A, B and C.

• Section A consists of 24 questions. Attempt any 20 questions from Q. No. 1 to 24.
• Section B also contains 24 questions. Attempt any 20 questions from Q. No. 25 to 48.
• Section C contains three Case Studies containing 12 questions and 4 questions in each case. Attempt any 10 from Q. No. 49 to 60.
• There is only one correct option for every multiple choice question (MCQ). Marks will not be awarded for answering more than one option.

There is no negative marking.

SECTION-A

Section – A consists of 24 questions. Attempt any 20 questions from this section.

The first attempted 20 questions would be evaluated.

Question 1.

A student took Sodium Sulphate solution in a test tube and added Barium Chloride solution to it. He observed that an insoluble substance has formed. The colour and molecular formula of the insoluble substance is:

1. Grey. Ba₂SO₄
2. Yellow. <math>Ba(SO_4)_2</math>
3. White. BaSO₄
4. Pink. BaSO₄

Question 2.

Which of the following oxide(s) is/are soluble in water to form alkalies?

1. Na₂O (ii) SO₂ (iii) K₂O (iv) NO₂
2. (i) and (iii)
3. (i) only
4. (ii) and (iv)
5. (iii) only

Question 3.

Study the diagram given below and identify the as formed in the reaction.

<math>\bigcirc</math> Dilute sulphuric acid-

Zinc granules

Α. Carbon di-oxide which extinguishes the burning candle.

В. Oxygen due to which the candle burns more brightly.

1. Sulphur dioxide which produces a suffocating smell.
2. Hydrogen which while burning produces a popping sound.

Question 4.

Sodium reacts with water to form sodium hydroxide and hydrogen gas. The balanced equation which represents the above reaction is;

1. <math>Na(s) + 2H2O(l) \rightarrow 2NaOH(aq) + 2H2(g)</math>

В. <math>2Na(s) + 2H2O(l) \rightarrow 2NaOH(aq) + H2(g)</math>

1. <math>2Na(s) + 2H2O(l) \rightarrow NaOH(aq) + 2H2(g)</math>
2. <math>2Na(s) + H2O(l) \rightarrow 2NaOH(aq) + 2H2(g)</math>

Question 5.

Which of the options in the given table are correct?

Option Natural Source Acid Present

1. Orange
2. Sour milk
3. Ant sting
4. Tamarind

1. (i) and (ii) В. (i) and (iv)
2. (ii) and (iii)
3. (iii) and (iv)

Question 6.

<math>C_6H_{12}O_6(aq) + 6O_2(aq) \rightarrow 6CO_2(aq) + 6H_2O(l)</math> The above reaction is a/an

1. Displacement reaction В. Endothermic reaction
2. Exothermic reaction
3. neutralisation reaction