Redox reactions

Q.

Which is the strongest reducing agent among the following metals:-

1. Magnesium
2. Zinc
3. Potassium
4. Calcium

Q.

Which is the most electropositive element among the following?

1. Aluminium

2. Sodium

3. Calcium

4. Copper

Q.

Why is hydrogen placed in the reactivity series?

Q.

Which metals can’t displace hydrogen from an acid and why? [3 MARKS]

Q.

Which of the following metals is/are stored in kerosene oil?

1. Magnesium

2. Aluminium

3. Sodium

4. Potassium

Q.

Aluminium is used as a reducing agent.

1. True

2. False

Q. Why do articles made of aluminum not corrode easily even aluminum is a highly reactive metal?

Q.

What would happen if sodium and potassium are kept in open air? [3 MARKS]

Q.

Some metals react with acids and evolve-

1. Oxygen gas
2. Hydrogen gas
3. Chlorine gas

4. Hydrogen sulphide gas

Q.

When potassium reacts with cold water then hydrogen gas burns with a _____ coloured flame.

1. lilac

2. pale blue

3. green

4. golden yellow

Q. Products formed when platinum wire is heated

Q.

How to remember reactivity series of metals?

Q.

Aluminium $Al$ is more reactive than Magnesium $Mg$.

1. True

2. False

Q.

What is the observation that can be made when calcium reacts with water?

1. Vigorous reaction

2. Calcium floats on water

3. Calcium does not react at all

4. Explosive reaction

Q. Question 7
Metals generally react with dilute acids to produce hydrogen gas. Which one of the following metals does not react with dilute hydrochloric acid?

(a) magnesium
(b) aluminium
(c) iron
(d) copper

Q.

K, Ca, Na, Mg, Al, Zn, Fe, Pb, Cu, Ag. Name one metal which reacts explosively with dilute sulphuric acid?

Q. Give suitable reasons for the following- (1). Can displacement reaction be a Redox reaction. (2). Gold and Platinum do not get affected even if there is presence of moist air or acidic gases . Why ? (3). Corrosion of Aluminium is considered to be advantageous.

Q. What happens when red hot charcoal is passed through water.

Q.

Mark ‘True’ if the statement is true and ‘False’ if it is false.​
(a) Generally, non-metals react with acids.​(b) Sodium is a very reactive metal.
(c) Copper displaces zinc from zinc sulphate solution.
(d) Coal can be drawn into wires.

Q.

Potassium reacts with water to produce _______ flame.

Q.

Which reaction represents a chemical combination?

1. 2NaHCO₃ → Na₂CO₃ + H₂O+ CO₂

2. CaO + H₂O → Ca(OH)₂

3. CuSO₄ + Fe → FeSO₄ + Cu

4. AgNO₃ + NaCl →AgCI + NaNO₃

Q. Question 3 (d)
Metals react with acids to produce ___ gas.

Q.

Which is the strongest reducing agent among the following metals?

1. Magnesium

2. Zinc

3. Potassium

4. Calcium

Q.

Which among the following is electropositive element?

1. Magnesium
2. Phosphorus
3. Sulphur
4. Chlorine

Q.

Why is phosphorus stored in water ?

Q.

Metallic reactivity decreases down the group.

1. True

2. False

Q.

Give one example of the following reaction:

Combination reaction

Q.

Based on the activity series, which of the following can be extracted by electrolysis?

1. Potassium

2. Sodium

3. Aluminum

4. Potassium, Sodium and Aluminium

Q.

The correct order of the tendency of metals in the activity series to reduce water is:-

1. $K>Ca>Mg>Na>Al>Zn$
2. $K>Na>Ca>Mg>Al>Zn$
3. $K<Na<Ca<Mg<Al<Zn$
4. $K>Na>Mg>Ca>Al>Zn$

Q.

Choose from the following list of substances, as to what matches the descriptions given below
Acetylene gas, aqua fortis coke, brass, barium chloride, bronze, platinum

A black powdery substance used for the
reduction of zinc oxide during its extraction.