Chemistry (Part-VIII) (Railway)

Total Questions: 50

1. Which of the following metals is the least reactive, as per the reactivity series of metals? [RRB Group D CBT Exam, 17.09.2022 (Shift-I)]

(1) Lead
(2) Zinc
(3) Magnesium
(4) Iron

Correct Answer: (1) Lead

Solution:

Among the given metals, Lead is the least reactive.

2. What are the main products in the process of neutralisation reaction? [RRB Group 'D' CBT Exam, 17.09.2022 (Shift-I)]

(1) CO₂ and salt
(2) H₂O and salt
(3) O₂ and salt
(4) N₂ and salt

Correct Answer: (2) H₂O and salt

Solution:A neutralisation reaction can be defined as a chemical reaction in which an acid and base quantitatively react together to form a salt and water as products.

• There is a combination of H⁺ ions and OH⁻ ions which form water.

• Example: HCl + NaOH → NaCl + H₂O

3. What is the difference between the molecular masses of two successive members of the homologous series? [RRB Group 'D' CBT Exam, 17.09.2022 (Shift-III)]

(1) 8 u
(2) 12 u
(3) 6 u
(4) 14 u

Correct Answer: (4) 14 u

Solution:

The successive members of a homologous series differ from each other by a -CH₂ group.

• The molecular mass of a -CH₂ group = 12 + 2 = 14.

• Hence, each successive homologue of a homologous series differ by a mass of 14 amu.

4. Which of the following substances is being oxidised in the given reaction? [RRB Group 'D' CBT Exam, 17.09.2022 (Shift-III)]

4Fe(s) + 3O₂(g) → 2Fe₂O₃(s)

(1) Fe(s)
(2) O₂(g)
(3) Both Fe(s) and Fe₂O₃(s)
(4) Fe₂O₃(s)

Correct Answer: (1) Fe(s)

Solution:

Oxidation is the gain of oxygen. Reduction is the loss of oxygen.

• In the reaction 4Fe(s) + 3O₂(g) → 2Fe₂O₃(s), Iron (Fe) gains oxygen to form Ferric Oxide. So, it is oxidised.

5. Which of the following chemical compounds is known as marble? [RRB Group 'D' CBT Exam, 17.09.2022 (Shift-III)]

(1) Calcium carbonate
(2) Calcium oxide
(3) Calcium bicarbonate
(4) Calcium hydroxide

Correct Answer: (1) Calcium carbonate

Solution:The chemical name of marble is calcium carbonate (CaCO₃).
• Marble, the hardest form of calcium carbonate, is a metamorphic rock.
• It forms as a result of the recrystallization process of limestone, under conditions of high pressure and temperature.

6. The compound 'X' is produced when baking soda is heated. Recrystallization of X gives compound 'Y'. Select the compounds X and Y, respectively. [RRB Group 'D' CBT Exam, 17.09.2022 (Shift-III)]

(1) Sodium carbonate and washing soda
(2) Sodium carbonate and bleaching powder
(3) Sodium bicarbonate and washing soda
(4) Sodium bicarbonate and bleaching powder

Correct Answer: (1) Sodium carbonate and washing soda

Solution:

When heated, baking soda produces sodium carbonate, carbon dioxide, and water.
• Then due to the recrystallization of sodium carbonate, it gives out washing soda.

• Na₂CO₃ + 10H₂O → Na₂CO₃.10H₂O.

7. Select the correct balanced chemical equation for the given reaction. [RRB Group 'D' CBT Exam, 17.09.2022 (Shift-III)]

Magnesium(s) + Oxygen(g) → Magnesium oxide(s)

(1) Mg(s) + O₂(g) → MgO(s)
(2) 2Mg(s) + O₂(g) → 2MgO(s)
(3) 2Mg(s) + O₂(g) → 2MgO₂(s)
(4) Mg(s) + O₂(g) → 2MgO(s)

Correct Answer: (2) 2Mg(s) + O₂(g) → 2MgO(s)

Solution:2Mg(s) + O₂(g) → 2MgO(s) is a combination reaction and an oxidation reaction where Mg is getting oxidized to form MgO.
• Here, 2 magnesium atoms react with a molecule of oxygen-producing 2 molecules of the compound magnesium oxide-releasing some heat in the process.

8. Which of the following statements about Mendeleev's periodic table is NOT correct? [RRB Group 'D' CBT Exam, 17.09.2022 (Shift-III)]

(1) Noble gases were not discovered at that time.
(2) Like alkali metals, hydrogen reacts with halogen, oxygen, and sulphur to form compounds having similar formulae.
(3) No specific position was assigned to the isotopes in the Mendeleev's periodic table.
(4) Hydrogen was assigned a fixed position in the Mendeleev's periodic table.

Correct Answer: (4) Hydrogen was assigned a fixed position in the Mendeleev's periodic table.

Solution:Hydrogen was assigned a fixed position in the Mendeleev's periodic table.
• Hydrogen had no fixed position in Mendeleev's Periodic Table.
• This was because it resembles alkali metals by forming positive ions and resembles halogens by forming diatomic molecules.
So, it was placed above both the groups and could not be given a fixed position.

9. Select the correct pair of semimetals amongst the following elements. [RRB Group 'D' CBT Exam, 17.09.2022 (Shift-II)]

(1) Carbon and nitrogen
(2) Sulphur and phosphorus
(3) Silicon and germanium
(4) Hydrogen and helium

Correct Answer: (3) Silicon and germanium

Solution:Silicon (Si) and germanium (Ge) have the characteristics of both metals and non-metals.
• Hence, they are semi-metals or metalloids.
• The six commonly recognised metalloids are boron, silicon, germanium, arsenic, antimony, and tellurium.

10. Which of the following is the least reactive metal in the reactivity series? [RRB Group 'D' CBT Exam, 19.09.2022 (Shift-II)]

(1) Ag
(2) Hg
(3) Cu
(4) Au

Correct Answer: (4) Au

Solution:Among Gold, Silver, Mercury and Copper, Gold is least reactive metal because of higher standard reduction potential value.
Platinum is the most non-reactive metal.

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Chemistry (Part-VIII) (Railway)

1. Which of the following metals is the least reactive, as per the reactivity series of metals? [RRB Group D CBT Exam, 17.09.2022 (Shift-I)]

2. What are the main products in the process of neutralisation reaction? [RRB Group 'D' CBT Exam, 17.09.2022 (Shift-I)]

3. What is the difference between the molecular masses of two successive members of the homologous series? [RRB Group 'D' CBT Exam, 17.09.2022 (Shift-III)]

4. Which of the following substances is being oxidised in the given reaction? [RRB Group 'D' CBT Exam, 17.09.2022 (Shift-III)]

5. Which of the following chemical compounds is known as marble? [RRB Group 'D' CBT Exam, 17.09.2022 (Shift-III)]

6. The compound 'X' is produced when baking soda is heated. Recrystallization of X gives compound 'Y'. Select the compounds X and Y, respectively. [RRB Group 'D' CBT Exam, 17.09.2022 (Shift-III)]

7. Select the correct balanced chemical equation for the given reaction. [RRB Group 'D' CBT Exam, 17.09.2022 (Shift-III)]

8. Which of the following statements about Mendeleev's periodic table is NOT correct? [RRB Group 'D' CBT Exam, 17.09.2022 (Shift-III)]

9. Select the correct pair of semimetals amongst the following elements. [RRB Group 'D' CBT Exam, 17.09.2022 (Shift-II)]

10. Which of the following is the least reactive metal in the reactivity series? [RRB Group 'D' CBT Exam, 19.09.2022 (Shift-II)]

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