Chemistry (Part-VI)

1. Soil is an example of which of the following? [S.S.C. Online MTS (T-I) 16.09.2017]

(a) Homogeneous mixture
(b) Molecule
(c) Compound
(d) Heterogeneous mixture

Correct Answer: (d) Heterogeneous mixture

Solution:Many types of mutually miscible and immiscible substances are found in soil. So the soil is a heterogeneous mixture.

2. The purest form of water in nature is- [S.S.C. Online Graduate Level (T-1) 3.09.2016]

(a) Rain water
(b) Lake water
(c) River water
(d) Sea water

Correct Answer: (a) Rain water

Solution:Rainwater is considered to be the purest in nature i.e. rainwater is the purest as compared to the water obtained from all known natural sources (river, sea, pond, lake, etc.), because it comes from natural sources (river, sea, etc.). As a result of the condensation of water vapor obtained from the evaporation of water, it comes to the earth in the form of rain. During the process of evaporation, all the impurities remain in the original source.

3. Atoms of which element combines with hydrogen to give water? [S.S.C. Online CGL (T-I) 18.08.2021]

(a) Nitrogen
(b) Carbon
(c) Oxygen
(d) lodine

Correct Answer: (c) Oxygen

Solution:Oxygen atoms combine with hydrogen atoms to form water. That is, a molecule of water (H₂O) is formed by combining two atoms of hydrogen and one atom of oxygen.

4. Which of the following types of water is known to be free from any impurity? [S.S.C. Online CHSL (T-I) 22.01.2017]

(a) Mineral Water
(b) Distilled Water
(c) Spring Water
(d) Boiled Water

Correct Answer: (b) Distilled Water

Solution:Distilled water is the water from which most impurities have been removed by the distillation process. Therefore, this water is considered completely free from impurities.

5. Which of the following elements can be used to treat/purify water? [S.S.C. Online M.T.S. (T-I) 13.10.2021 (Shift-III)]

(a) Magnesium
(b) Lead
(c) Chlorine
(d) Potassium

Correct Answer: (c) Chlorine

Solution:Chlorine (Cl) is one such element, which is found as a gas at normal temperature and pressure and has strong disinfectant properties. It is chlorinated to disinfect the water. This work is done with the help of bleaching powder [Ca(OCl)₂].

6. Which method will be employed to test the hardness of water? [S.S.C. Online Graduate Level (T-I) 11.09.2016]

(a) Boiling
(b) Distiliation
(c) Formation of lather with soap
(d) None of these

Correct Answer: (c) Formation of lather with soap

Solution:

The method of making lathes with soap is used to teat the hardone of the war. The sales of calciom and magicstam sulliste are dissolved in hant water, due which do not for very little lachea

7. Which of the following is used for removing the permanent hardness of water? [S.S.C. Online Graduate Level (T-I) 7.03.2020]

(a) Baking Soda
(b) Bleaching Powder
(c) Lime
(d) Washing Soda

Correct Answer: (d) Washing Soda

Solution:"Hard water does not lather easily with soap. The permanent hardness of water is due to chloride and sulfate salts of calcium and magnesium dissolved in water and can be removed by washing soda (Na₂CO₃)."

8. Which of the following reacts with water? [S.S.C. Online Constable GD 12.02.2019]

(a) Silver
(b) Calcium
(c) Lead
(d) Copper

Correct Answer: (b) Calcium

Solution:

Calcium (Ca) reacts very actively with water. When a piece of calcium is put in water, bubbles start rising and hydrogen gas is produced.

$2H_2O \rightarrow Ca(OH)_2 + H_2$

Silver, lead, and copper generally does not react with water.

9. Which of the following statements are CORRECT? [S.S.C. Online CHSL (T-I) 22.03.2018]

I. The soap molecules form structures called micelles.

II. Soap micelles cannot scatter light.

III. Oily dirt gets collected in the center of the micelle.

(a) Both I and II
(b) Both I and III
(c) Both II an III
(d) All I, II and III

Correct Answer: (b) Both I and III

Solution:Structures made of soap molecules form micelles, which contain a hydrophilic group and a hydrophobic group. Dirt (containing oil) itself is also hydrophobic. So it gets attached to this group of micelles, while the hydrophilic group of micelles attaches to water (which is polar), so the scum is drawn to the center of the micelle.

10. Which among the following has the maximum density? [S.S.C. Online CHSL (T-I) 9.01.2017]

(a) Water
(b) Ice
(c) Ethylene
(d) Acetone

Correct Answer: (a) Water

Solution:Water has the highest density compared to ethylene, acetone, and ice.