Thursday, 25 February 2021

CBSE Class 7 Science - MCQ and Online Tests - Unit 5 - Acids, Bases and Salts

CBSE Class 7 Science – MCQ and Online Tests – Unit 5 – Acids, Bases and Salts


 

Every year CBSE students attend Annual Assessment exams for 6,7,8,9,11th standards. These exams are very competitive to all the students. So our website provides online tests for all the 6,7,8,9,11th standards’ subjects. These tests are also very effective and useful for those who preparing for any competitive exams like Olympiad etc. It can boost their preparation level and confidence level by attempting these chapter wise online tests.

These online tests are based on latest CBSE syllabus. While attempting these, our students can identify their weak lessons and continuously practice those lessons for attaining high marks. It also helps to revise the NCERT textbooks thoroughly

CBSE Class 7 Science – MCQ and Online Tests – Unit 5 – Acids, Bases and Salts

Choose the correct answer:

Question 1.
Phenolphthalein is a synthetic indicator and its colours in acidic and basic solutions, respectively are:
(a) red and blue
(b) blue and red
(c) pink and colourless
(d) colourless and pink

Answer

Answer: (d) colourless and pink


Question 2.
On adding phenolphthalein indicator to a colourless solution, no change is observed. What is the nature of this solution?
(a) Basic
(b) Either acidic or basic
(c) Either acidic or neutral
(d) Either basic or neutral

Answer

Answer: (c) Either acidic or neutral


Question 3.
Out of these gases which one is used in fire extinguishers
(a) CO2
(b) SO2
(c) NO2
(d) H2S

Answer

Answer: (a) CO2


Question 4.
The correct way of making a solution of acid in water is to
(a) add water to acid
(b) add acid to water
(c) mix acid and water simultaneously
(d) add water to acid in a shallow container

Answer

Answer: (b) add acid to water


Question 5.
Products of a neutralisation reaction are always:
(a) an acid and a base
(b) an acid and a salt
(c) a salt and water
(d) a salt and a base

Answer

Answer: (c) a salt and water


Question 6.
An oxide is acidic and has a pungent odour. It could be
(a) sulphur dioxide
(b) carbon dioxide
(c) sodium oxide
(d) nitrogen dioxide

Answer

Answer: (d) nitrogen dioxide


Question 7.
Phenolphthalein is a synthetic indicator and its colours in acidic and basic solutions, respectively are:
(a) red and blue
(b) blue and red
(c) pink and colourless
(d) colourless and pink

Answer

Answer: (d) colourless and pink


Question 8.
When the soil is too basic, plants do not grow well in it. To improve its quality what must be added to the soil?
(a) Organic matter
(b) Quick lime
(c) Slaked lime
(d) Calamine solution

Answer

Answer: (a) Organic matter


Question 9.
Which of the following set of substances contain acids?
(a) Grapes, lime water
(b) Vinegar, soap
(c) Curd, milk of magnesia
(d) Curd, vinegar

Answer

Answer: (d) Curd, vinegar


Question 10.
On adding phenolphthalein indicator to a colourless solution, no change is observed. What is the nature of this solution?
(a) Basic
(b) Either acidic or basic
(c) Either acidic or neutral
(d) Either basic or neutral

Answer

Answer: (c) Either acidic or neutral


Question 11.
Which of the following is an acid-base indicator?
(a) Vinegar
(b) Lime water
(c) Turmeric
(d) Baking soda

Answer

Answer: (c) Turmeric

 

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