Test: Introduction to Acids & Bases


20 Questions MCQ Test Science & Technology for UPSC CSE | Test: Introduction to Acids & Bases


Description
Attempt Test: Introduction to Acids & Bases | 20 questions in 15 minutes | Mock test for Class 10 preparation | Free important questions MCQ to study Science & Technology for UPSC CSE for Class 10 Exam | Download free PDF with solutions
QUESTION: 1

The acid present in curd is:

Solution:

The acid present in curd is lactic acid. Curd forms due to the chemical reaction between lactic acid bacteria and milk protein casein. The increased acidity causes the milk proteins (casein) to tangle into solid masses or curds.

QUESTION: 2

Which of the following properties is NOT shown by bases?

Solution:

Blue litmus paper turns red under acidic conditions. It will turn red when it comes into contact with an acid. If it comes into contact with a substance that is basic or neutral, it will remain blue.

QUESTION: 3

Which of the following acid is a weak acid?

Solution:

Acids like acetic acid (CH3COOH) dissociate partially or incompletely, releasing only some of their hydrogen atoms into the solution. Hence it is a weak acid.

QUESTION: 4

The natural source of Acetic acid is:

Solution:

Option A: Lactic acid is found in curd
Option B: Citric acid is found in Oranges
Option C: Oxalic acid is found in tomatoes
Option D: Acetic acid is found in vinegar

Thus, option D is correct.

QUESTION: 5

Lime water is

Solution:

Limewater is the common name for a dilute aqueous solution of calcium hydroxide.
Calcium hydroxide, Ca(OH)2, is sparsely soluble at room temperature in water (1.5 g/L at 25 °C). It is basic in nature with a pH of 12.4.

QUESTION: 6

Which of the following is a strong base?

Solution:

KOH (aq), or Potassium Hydroxide, is a strong base. When added to water, it dissociates completely to give mobile ions, including the hydroxide ion which is responsible for the alkaline properties of the substance.

QUESTION: 7

The difference of molecules of water in gypsum and PoP is

Solution:

Gypsum: CaSO44.2H​2O
Plaster of paris: CaSO4​.0.5H2​O.

The difference in number of water molecules is = 2 - 0.5 = 1.5 = 3/2

QUESTION: 8

Which of the following is NOT an organic acid?

Solution:

Sulfuric acid is inorganic because it doesn't contain carbon atoms bonded to oxygen, nitrogen and hydrogen atoms. 

QUESTION: 9

Which one of the following is acidic/slightly acidic?

Solution:

Option A: Lemon juice in its natural state is acidic with a pH of about 2, but once metabolized it actually becomes alkaline with a pH well above 7. So, outside the body, anyone can see that lemon juice is very acidic.

Option B: Tomatoes are on the low end of acidic foods. An alkaline diet is not that you can not have any foods that are acidic but a balance of both alkaline and acidic.

Option C: Milk is actually pretty close to neutral with a pH of 6.8 (slightly acidic). It can become acidic if bacteria break down the milk sugar and produce lactic acid. This is what causes milk to sour.

Thus, option D is correct.

QUESTION: 10

Which of the following acid is present in tamarind?

Solution:

The acid that is present in tamarind is tartaric acid, which is a white crystalline organic acid.

QUESTION: 11

We should never add water to acid because:

Solution:

If we add water to acid, the reaction would become highly exothermic and lots of heat would be generated which would splash​ on your face and cause severe burns.

QUESTION: 12

Which of the following properties is not shown by acids ?

Solution:

Acids dissociate in water to give H+ ions and not OH-. OH- ions are released on dissociation of bases in water.

QUESTION: 13

Acids when dissolved in water produce:

Solution:

Most acids release H+ ions in water, which combines with water molecules to produce hydronium (H3O+) ions.
Example: HCl(g) + H2O(l) → Cl(aq) + H3O+(aq)

QUESTION: 14

A substance ‘A’ does not dissociate completely into its ions in aqueous solutions. It is bitter in taste and soapy to touch.Identify the substance A.

Solution:

A base is bitter in taste and soapy to touch. A weak base does not dissociate completely into its ions in aqueous solutions.

QUESTION: 15

Select the substance which shows acidic behavior in its aqueous solution.​

Solution:

Acid is defined as the substance which dissociates and releases H+ ions in their aqueous states.
HCl (aq.) gives H+ (aq.) in aqueous solution.
But molecules like alcohol, glucose, and Urea do not produce H+ ions and thus are not considered acids.

QUESTION: 16

Find the odd one out:

Solution:

CuSO4.5H2O is a hydrated salt. An example of acid salt is NaHCO3.

QUESTION: 17

Which one will NOT change red litmus to blue?

Solution:

HCL is an acid so it won't have any effect on red litmus paper

QUESTION: 18

Select the one which is WRONGLY mapped

Solution:

Calcium Hydroxide (not carbonate) is commonly referred to as slaked lime.

QUESTION: 19

Name an element which is common to all acids?

Solution:

An element which is common to all acids is Hydrogen because acids dissociate into H+ ions.

QUESTION: 20

Name an acid which contains both oxygen and hydrogen?

Solution:

An oxyacid is an acid that contains an oxygen atom bonded to a hydrogen atom and at least one other element.
General structure: X-O-H

Use Code STAYHOME200 and get INR 200 additional OFF
Use Coupon Code