Physical and Chemical Properties of Hydrogen

Q.

Why is losing electrons called oxidation? Give an example.

Q.

Explain the electronic concept of oxidation and reduction. [3 MARKS]

Q.

Fatty foods become rancid due to process of

1. Reduction

2. Oxidation

3. Hydration

4. None of the above

Q.

Hydrogen acts as a reducing agent by taking:-

1. lithium

2. potassium

3. oxygen

4. sodium

Q.

What do we call the substance which either slows down or stops the reaction from proceeding further?

1. Prohibitor

2. Inhibitor

3. Limiting reagent

4. Catalyst

Q.

How does pure hydrogen gas burns?

1. Lilac-coloured flame with no sound

2. Pale blue flame with no sound

3. Colourless flame with a popping sound

4. Pale blue flame along with a popping sound

Q.

Which of the following displaces oxygen from water?

1. ${\mathrm{F}}_2$

2. ${\mathrm{Cl}}_2$

3. ${\mathrm{Br}}_2$

4. ${\mathrm{I}}_2$

Q.

How would you show that hydrogen :

(a) is a non-supporter of combustion ?

(b) is lighter than air ?

Q.

Oxidation is defined as the loss of hydrogen or gain of oxygen.

1. True

2. False

Q. Hydrogen - oxygen mixture is called as __________ mixture

Q.

What is oxidation?

Q.

(a) Equal volumes of hydrogen and chlorine are exposed to diffused sunlight to prepare

(i) hydrogen chloride

(ii) water

(iii) sodium hydroxide

(iv) hydrochloric acid

(b) The metal which reacts with cold water to produce hydrogen is

(i) magnesium

(ii) aluminium

(iii) calcium

(iv) iron

(c) In metal reactivity series the more reactive metals are at

(i) top

(ii) bottom

(iii) middle

(iv) none

(d) Hydrogen is responsible for producing

(i) heat and light

(ii) hydrogenated oil

(iii) fertilizers

(iv) all of the above

(e) Hydrogen is

(i) combustible

(ii) non-combustible

(iii) supporter of combustion

(iv) neither supporter nor combustible

(f) Water gas is a mixture of

(i) carbon monoxide and oxygen

(ii) carbon monoxide and hydrogen

(iii) hydrogen and oxygen

(iv) hydrogen and nitrogen

Q. On complete combustion of copper why is a green flame given off(as in, why not a flame of any other colour)?

Q.

What happens when hydrogen combines with chlorine in diffused light?

Q.

Hydrogen gas smells like rotten eggs.

1. True
2. False

Q. 30. What is the Oxidation product of hexan-3-one using selenium dioxide?

Q.

Define hygroscopic , efflorescence , deliquenscene

Q.

Which of the following are the uses of oxygen?

1. The process of combustion is supported by oxygen.

2. All of the above

3. It helps in respiration.

4. It is used as a fuel in rockets.

Q.

Mention one example each for the different types of chemical reactions.

Q.

Which of the following is the most abundant element in the universe?

1. Oxygen

2. Helium

3. Hydrogen

4. Nitrogen

Q.

After the power cut Priya lighted a candle and stated thinking why there is a flame in candles. What do you think so?

Q.

Which of the following statement is true about the oxidation process?

1. Loss of electron

2. Addition of oxygen

3. Addition of hydrogen

4. All of the above

Q.

Nowadays silver ware blackens faster than it did during our grandparents time what do you think could be the reason

Q.

What is a reducing agent?

Is hydrogen a reducing agent.

Q.

Write the uses of Hydrogen and Phosphorus.

Q.

Identify the following substances :

Gas $C$ has an offensive smell like rotten eggs.

Q.

Find the odd one out.Give a reason for your answer.

1. Oxygen

2. Hydrogen

3. Sugar

4. Carbon dioxide

5. Nitrogen

Q. What is meant by oxidised?

The nitric oxide is oxidised again and nitrogen dioxide is formed

Q. An unknown substance X, reacts with water to produce a gas Y which burns with a pop sound. Identify X and Y.
*More than one option may be correct.

1. X = Calcium, Y = Hydrogen
2. X = Nitrogen, Y = Nitrogen dioxide
3. X = Lithium, Y = Hydrogen
4. X = Carbon, Y = Hydrogen

Q.

Which of the following substances is a good oxidizing agent?

1. Coke

2. Calcium

3. Hydrogen peroxide

4. Sodium