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 correct ?
[A] Oxidation takes place at Cathode and Reduction Takes Place at Anode
[B] Oxidation takes place at Anode and Reduction Takes place at Cathode
[C] Both Oxidation and Reduction takes place at cathode
[D] Both Oxidation and Reduction takes place at Anode
Show Answer
Correct Answer: B [Oxidation takes place at Anode and Reduction Takes place at Cathode]
Notes:
In an electrochemical cell, the half cell where oxidation takes place is known as oxidation half cell and the half cell where reduction takes place is known as reduction half cell. Oxidation takes place at anode which is negatively charged and reduction takes place at cathode which is positively charged.
2. Which among the following of a catalyst does not change at the end of a reaction?
[A] Quantity
[B] Chemical Composition
[C] Both Quantity and Chemical com position
[D] None of the above
Show Answer
Correct Answer: C [Both Quantity and Chemical com position]
Notes:
A catalyst is a substance that increases the rate of a chemical reaction without undergoing any permanent change itself. At the end of the reaction, a catalyst retains its original quantity and chemical composition. This property allows it to be used repeatedly in reactions. For example, enzymes, which are biological catalysts, remain unchanged after facilitating biochemical reactions.
3. What is the atomic number of Transuranic elements?
[A] Greater than 90
[B] Greater than 92
[C] Greater than 91
[D] Greater than 93
Show Answer
Correct Answer: B [Greater than 92]
Notes:
Transuranic elements are those with atomic numbers greater than 92, which is the atomic number of uranium. These elements, including plutonium (94) and americium (95), are all synthetic and typically unstable, often used in nuclear applications and research. The term “transuranic” specifically refers to elements beyond uranium in the periodic table.
4. Which among the following is correct regarding the alkaline battery ?
[A] Negative terminal made of Zinc Powder and Positive terminal made of Manganese dioxide & electrolyte is KOH
[B] Negative terminal made of Manganese dioxide and Positive terminal made of Zinc powder & electrolyte KOH
[C] Negative terminal made of Zinc Powder and Positive terminal made of Manganese dioxide & Electrolyte is Ammonium Chloride
[D] Negative terminal made of Manganese dioxide and Positive terminal made of Zinc powder & electrolyte Ammonium Chloride
Show Answer
Correct Answer: A [Negative terminal made of Zinc Powder and Positive terminal made of Manganese dioxide & electrolyte is KOH]
Notes:
The correct statement is that in an alkaline battery, the negative terminal is made of zinc powder, the positive terminal is made of manganese dioxide, and the electrolyte is potassium hydroxide (KOH). Alkaline batteries are known for their long shelf life and higher energy density compared to zinc-carbon batteries. They were invented in the 1950s and are widely used in household devices.
5. Aluminum is getting popular worldwide today as a “Green Metal”. Which among the following properties of Aluminum makes it a Green Metal?
[A] Aluminum has been providing a replacement of wood for saving forests and contributes in environment protection
[B] Aluminum is a light metal and it is resistant to corrosion
[C] Aluminum has fairly high rate of recycling and it can be re-used repeatedly without its quality deteriorating
[D] The lands after the Bauxite mining can be restored very quickly and easily
Show Answer
Correct Answer: C [Aluminum has fairly high rate of recycling and it can be re-used repeatedly without its quality deteriorating]
Notes:
Aluminum is considered a “Green Metal” primarily due to its high recycling rate. Approximately 75% of all aluminum ever produced is still in use today, as it can be recycled indefinitely without losing quality. This process saves energy—recycling aluminum uses about 95% less energy than producing new aluminum from bauxite ore. Additionally, recycling reduces greenhouse gas emissions and conserves natural resources, making aluminum a sustainable choice in various applications.
6. Which among the following is correct statement about both rusting of iron and respiration?
[A] Both are exothermic reactions
[B] Both are endothermic reactions
[C] While Rusting is endothermic, respiration is exothermic
[D] While Rusting is exothermic, respiration is endothermic
Show Answer
Correct Answer: A [Both are exothermic reactions]
Notes:
Both are oxidation-therefore exothermic processes
7. Ground Level Ozone is formed due to reaction between:
[A] VOCs, Oxides of Nitrogen & Sunlight
[B] VOCs, Sulphur dioxide & Sunlight
[C] Ozone, Sulphur dioxide & Oxides of Nitrogen
[D] Ozone, Oxides of Nitrogen & Sunlight
Show Answer
Correct Answer: A [VOCs, Oxides of Nitrogen & Sunlight]
Notes:
Ground Level Ozone results from photochemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOCs) in the presence of sunlight.
8. 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.
9. The presence of which of the following chemical elements helps to differentiate between sweet and sour crude oil?
[A] Iron
[B] Sulphur
[C] Vanadium
[D] Chromium
Show Answer
Correct Answer: B [ Sulphur ]
Notes:
Crude oil with high amount of Sulphur is termed as sour and with less Sulphur is called the sweet grade. Sour grade crude requires extra processing cost.
10. Which of the following is correct about the first ionization enthalpy of alkaline earth metals?
[A] It is higher than corresponding Group 1 metals
[B] It is lower than corresponding Group 1 metals
[C] No fix pattern exist
[D] None of the above
Show Answer
Correct Answer: A [It is higher than corresponding Group 1 metals]
Notes:
The first ionization enthalpy of these metals is higher than corresponding Group 1 metals due to the small size of these elements compared to the corresponding alkali metals. The second ionization enthalpy of these metals is lower than corresponding alkali metals.
