General Science Chemistry MCQs
Chemistry Objective (Multiple Choice) General Knowledge Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examination
11. How can we prepare Hydrogen at our home?
- Immersing alkali metals in water at room temperature
- Pouring Sulphuric acid on a copper plate
- Boiling zinc with caustic soda
- Passing electric current through rainwater
Select the correct option from the codes given below:
[A] Only 1 & 2
[B] Only 1, 3 & 4
[C] Only 2, 3 & 4
[D] 1, 2, 3 & 4
Show Answer
Correct Answer: D [ 1, 2, 3 & 4]
Notes:Some key notes about Hydrogen:
- Hydrogen does not occur in free state in atmosphere. Hydrogen is a vital constituent of all the compounds which are known in animal and plant kingdom.
- Hydrogen can be prepared by the action of water or steam on metals.
- Hydrogen can be prepared by the action of dilute HCl or Dilute H2SO4 on the metals.
- Hydrogen can be prepared by boiling powdered metals like zinc, aluminum, tin and lead with concentrated solution of caustic soda.
- Hydrogen can be prepared by passing electric current through acidulated water.
- Hydrogen is a colorless and odorless gas having no taste. It is the lightest element and is practically insoluble in water.
- Hydrogen is prepared in lab by the action of dilute sulphuric acid on granulated zinc. If copper sulphate is added to the above reactants, the reaction speeds up.
- Hydrogen is neutral towards litmus.
- Hydrogen reacts with oxygen to form water as the only product. It reacts with chlorine gas to form hydrogen chloride gas.
- Hydrogen is a good reducing agent and reduces metallic oxides to metals
- Hydrogen is used for (i) filling weather observation balloons, (Ii) the manufacture of chemicals, (iii) the hydrogenation of oils, (iv) the extraction of metals from their oxides, and (v) cutting and welding purposes.
- A mixture of hydrogen and oxygen burns with a characteristic pop sound. It is a test for hydrogen.
12. Consider the following:
- Atomic number
- Atomic mass
- Number of protons
- Number of neutrons
Which among the above is / are same for each of C-12, C-13 and C-14?
[A] 1 & 3
[B] 2 & 4
[C] 2 & 3
[D] 1 & 4
Show Answer
Correct Answer: A [ 1 & 3]
Notes:
Isotopes contain equal numbers of protons but different numbers of neutrons.
13. Which of the following chemicals being used as major ingredients of Bakery Industry in India, are said to cause cancer?
- Potassium bromate
- Potassium iodate
- Potassium sulfate
- Potassium chromate
Select the correct option from codes given below:
[A] 1 & 2 Only
[B] 2 & 3 Only
[C] 3 & 4 Only
[D] 1 & 4 Only
Show Answer
Correct Answer: A [ 1 & 2 Only]
Notes:
While potassium bromate is said to be a Class 2B carcinogenic, which means it may cause cancer, potassium iodate can lead to “thyroid disorders, increase the incidence of autoimmune thyroid it is and increase the risk of thyroid cancer.
14. Consider the following:
1. Nitrous acid
2. Nitric acid
3. Sulfuric acid
4. Hydrochloric acid
Which among the above are common in Acid rains?
[A] Only 1 & 2
[B] Only 2 & 3
[C] Only 2, 3 & 4
[D] Only 1, 2 & 3
Show Answer
Correct Answer: D [ Only 1, 2 & 3]
Notes:
Acid rain results from by- products of industry and the internal combustion engine, nitrogen and sulfur. The common acids in acid rain are nitrous acid, nitric acid, and sulfuric acid.
15. Acid rain is capable of damaging the buildings and historic monuments which are made up of rocks such as limestone and marble. Which among the following is the end product of such
reaction?
[A] Quick Lime
[B] Calcium Carbonate
[C] Calcium Hydroxide
[D] Gypsum
Show Answer
Correct Answer: D [ Gypsum]
Notes:
Acid rain is capable of damaging the buildings and historic monuments which are made up of rocks such as limestone and marble. This is because these rocks contain a large amount of Calcium Carbonate, which reacts with the Sulfuric Acid to create Gypsum. Gypsum flakes off easily. This is shown in the following reaction: CaC03 (s) + H2S04 (aq) – CaS04 (aq) + C02 (g) + H20 (I)
16. Double Sulphitation is the most commonly used method in India for refining of _?
[A] Crude oil
[B] Cooking oils
[C] Sugar
[D] Coal
Show Answer
Correct Answer: C [ Sugar]
Notes:
In India, the Double Sulphitation is the most commonly used method for refining of sugar. Also, it is the cheapest process of refining sugar as compared to other available process.
17. Which of the following is not a metalloid?
[A] Boron
[B] Silicon
[C] Germanium
[D] Titanium
Show Answer
Correct Answer: D [ Titanium]
Notes:
The most commonly recognised metalloids are boron, silicon, germanium, arsenic, antimony and tellurium. The other less recognised metalloids are: carbon, aluminium, selenium, polonium and astatine.Titanium is a lustrous transition metal with a silver color, low density and high strength.
18. Consider the following pairs:
- Water glass – Sodium silicate
- Mohr’s salt – Ferrous ammonium sulphate
- Caustic soda – Sodium hydroxide
Which of the above is/are correct?
[A] 1 & 2 Only
[B] 3 Only
[C] 2 & 3 Only
[D] 1, 2 & 3
Show Answer
Correct Answer: D [ 1, 2 & 3]
Notes:
All given pairs are correctly matched
19. Consider the following differences between Hard water and Soft water:
- While hard water has high calcium and magnesium content, soft water has high sodium content
- Hard water does not easily lather with soap, whereas soft water easily lather with soap
Which of the above statements is/are correct?
[A] 1 Only
[B] 2 Only
[C] Both 1 & 2
[D] Neither 1 nor 2
Show Answer
Correct Answer: C [ Both 1 & 2]
Notes:
Both are correct statements
Hard water is generally found in areas where groundwater is in contact with limestone, chalk and dolomite and gets higher amount of calcium and magnesium dissolved in it. Soft water is found in areas where groundwater usually travels through peat, igneous rock or sandstone sources, and does not contain as much calcium and magnesium. In fact, it contains higher amount of sodium ions.
20. Consider the following statements:
- Water has high specific heat capacity of than ice
- Heat capacity of cooking oil is lower than the heat capacity of water
Which of the above statements is/are correct?
[A] 1 Only
[B] 2 Only
[C] Both 1 & 2
[D] Neither 1 nor 2
Show Answer
Correct Answer: C [ Both 1 & 2]
Notes:
Both are correct statements
The hydrogen bonding between the molecules of water is higher than the bonding between the molecules of Oil. So it means that more heat energy is required to break the bonds of molecules of water
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