SSC CGL (Prelims) GK: Chemistry questions with solutions

Q1. Who reconciled Dalton's atomic hypothesis with Gay-Lussac's results on the combination of volumes in 1811?

1. Robert Boyle
2. Amadeo Avogadro
3. Fred Hoyle
4. Jacques Charles

Answer: Amadeo Avogadro

Amadeo Avogadro explained the discrepancy by proposing that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules. This reconciled Dalton’s atomic hypothesis with Gay-Lussac’s law of combining volumes.

Q2. Which of the following elements is a metalloid?

1. Iron
2. Oxygen
3. Sodium
4. Silicon

Answer: Silicon

Silicon is a metalloid, meaning it has properties intermediate between metals and non-metals. Iron, oxygen, and sodium are not metalloids.

Q3. The cause of a redox reaction is the:

1. transfer of electrons between two reactants
2. transfer of electrons between two products
3. transfer of neutrons between two reactants
4. exchange of halogens between two reactants

Answer: transfer of electrons between two reactants

Redox reactions involve simultaneous oxidation and reduction, which occur through transfer of electrons. This electron transfer changes oxidation states of the reactants.

Q4. What is the chemical symbol for sodium?

1. Na
2. S
3. So
4. N

Answer: Na

The chemical symbol for sodium is Na, derived from its Latin name 'natrium'.

Q5. Which of the following is a chemical change?

1. Melting of ice
2. Evaporation of water
3. Burning of paper
4. Boiling of milk

Answer: Burning of paper

Burning of paper is a chemical change because it produces new substances such as ash, carbon dioxide, and water vapor. The other options are physical changes involving only a change of state.

Q6. What is the chemical formula for washing soda?

1. Na₂CO₃
2. NaHCO₃
3. NaCl
4. NaOH

Answer: Na₂CO₃

Washing soda is sodium carbonate, whose chemical formula is Na₂CO₃. Sodium bicarbonate is baking soda, which has the formula NaHCO₃.

Q7. Which of the following is a homogeneous mixture?

1. Oil and water
2. Sand and iron
3. Salt and water
4. Mud and water

Answer: Salt and water

A homogeneous mixture has uniform composition throughout. Salt dissolves completely in water to form a solution, so it is homogeneous. The other options are heterogeneous mixtures.

Q8. What is the chemical symbol for gold?

1. Go
2. Au
3. Ag
4. Gd

Answer: Au

The chemical symbol for gold is Au, derived from its Latin name, aurum. The other symbols represent different elements. This is a basic chemistry fact.

Q9. Which gas is used in the manufacture of fertilizers?

1. Oxygen
2. Nitrogen
3. Carbon Dioxide
4. Hydrogen

Answer: Nitrogen

Nitrogen is widely used in fertilizer manufacture, especially in the production of ammonia and nitrogen-based fertilizers. It is a major industrial raw material in the fertilizer industry.