Chemistry MCQs
Chemistry Objective (Multiple Choice) General Knowledge Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examination.
1. Which among the following is the correct decreasing of bio elements in Human Body?
[A] oxygen, hydrogen, Carbon, nitrogen, calcium, and phosphorus
[B] oxygen, carbon, nitrogen, hydrogen, calcium, and phosphorus
[C] oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus
[D] carbon, oxygen, hydrogen, nitrogen, calcium, and phosphorus
Show Answer
Correct Answer: C [oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus ]
Notes:
In the human body the most common bio-elements (in decreasing order of occurrence) are oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Other bio-elements include sodium, potassium, magnesium, and copper.
2. When Ozone is heated its volume will…. ?
[A] increases
[B] decreases
[C] remains unchanged
[D] First Increase, then decrease
Show Answer
Correct Answer: C [remains unchanged]
Notes:
When Ozone is heated its volume will remain unchanged. It might change volume to an extent but not to a great extent.
3. Which of the following best describes the nature of Froth and Foam?
[A] Solid suspended in gas
[B] Liquid suspended in gas
[C] Gas suspended in liquid
[D] Gas suspended in solid
Show Answer
Correct Answer: C [Gas suspended in liquid]
Notes:
Froth and foams are examples of “gas suspended in liquid”. They are typically created when gas bubbles are dispersed in a liquid. This physical phenomenon is commonly observed in many daily life scenarios such as soap lather and carbonated drinks. Technically, they are a special case of colloid where little blobs of one liquid are dispersed in another and show the property of surface tension.
4. Which among the following impurity in drinking water causes the “Bamboo Spine” disorder?
[A] Nitrate
[B] Fluorides
[C] Arsenic
[D] Sulphides
Show Answer
Correct Answer: B [ Fluorides]
Notes:
Ankylosing Spondylitis is a chronic, inflammatory arthritis and autoimmune disease that mainly affects joints in the spine and the sacroiliac joints in the pelvis. It tends to affect the spine and in late stages, the spine will fuse and this has given rise to the term “bamboo spine”. It is mainly caused due to impurities in drinking water associated with fluorides.
5. What is the general Q-value for alpha-decay?
[A] greater than 0
[B] less than 0
[C] equal to 0
[D] None of the above
Show Answer
Correct Answer: A [greater than 0]
Notes:
Q-value is the net kinetic energy gained in the process or, if the initial nucleus X is at rest, the kinetic energy of the products. Clearly, Q> 0 for exothermic processes such as α-decay.
6. What do we call the number of water molecules present in one formula unit of a salt?
[A] Formula number of salt
[B] Power of the salt
[C] Water of crystallisation
[D] Hydro number
Show Answer
Correct Answer: C [Water of crystallisation]
Notes:
The fixed number of water molecules present in one formula unit of a salt is called water of crystallisation. For example, one formula unit of copper sulphate has five molecules of water in it.
7. How many molecules of water Gypsum has, as a water of crystallisation?
[A] 4
[B] 2
[C] 7
[D] 9
Show Answer
Correct Answer: B [2]
Notes:
Gypsum has two molecules of water as water of crystallisation. So, the chemical formula for hydrated gypsum becomes CaSO4.2H2O. This gypsum on getting heated loses water molecules and becomes calcium sulphate hemihydrate (CaSO4.1/2H2O). This is known as plaster of Paris.
8. Which of the following is an example of secondary battery?
[A] Mercury cell
[B] Nickel-cadmium cell
[C] Dry cell
[D] All of the above
Show Answer
Correct Answer: B [Nickel-cadmium cell]
Notes:
Nickel-cadmium cell is an example of secondary battery. It has longer life than the lead storage cell but more expensive to manufacture.
9. What are the by-products of a hydrogen fuel cell?
[A] Water, heat and ozone
[B] Water and heat
[C] Water and ozone
[D] Heat, methane and Carbon dioxide
Show Answer
Correct Answer: B [Water and heat]
Notes:
The only by-products in a fuel cell by combining hydrogen and oxygen are water and heat. They do not emit greenhouse gases or other air pollutants.
10. Propanol belongs to which of the following group?
[A] Alcohol
[B] Aldehyde
[C] Carboxylic acid
[D] Ketone
Show Answer
Correct Answer: A [Alcohol]
Notes:
Propanol belongs to Alcohol group. Alcohols are suffixed with ‘ol’ and have a functional group OH attached to them. For example: Butanol, Propanol etc.
