Flame Characteristics

Q.

Explain why alkanes are excellent fuels.

Q.

The gas used in welding and cutting metals is _______.

1. Propene

2. Ethane

3. Ethyne

4. Ethene

Q. The bottom of cooking vessels gets blackened when used on a gas/kerosene stove due to incomplete combustion of the fuel.

1. True
2. False

Q.

‘‘A compound $\mathrm{X}$on combustion gives a yellow flame with lots of smoke".What inference would you draw from this statement?

Q.

An organic compound burns with a sooty flame. Is it saturated or unsaturated compound?

Q. Coal doesn't produce a flame upon burning while LPG does? How do you account this?

Q.

A burning candle produces a luminous flame.

1. True
2. False

Q.

What type of fuels :
(a) burn with a flame?
(b) burn without a flame?

Q. One of the following burns without producing a flame. This is :
(a) wood (b) charcoal (c) LPG (d) candle

Q.

The substances which easily catch fire in air or oxygen are called,

1. flammable substances

2. combustible substances

3. either (A) and (B)

4. heat sensitive substances

Q.

The bottom of cooking vessels gets blackened when used on gas/kerosene stove on due to:

1. Incomplete combustion of fuel

2. Over combustion of fuel

3. None of the above

4. Complete combustion of fuel

Q.

The fuel which usually burns with a blue flame is :
(a) coal (b) LPG (c) candle wax (c) kerosene (in lamp)

Q. (a) Distinguish between the saturated hydrocarbon ethane and the unsaturated hydrocarbon ethene by drawing their structural formulae.
(b) Addition reaction and substitution reactions are types of organic reactions. Which type of reaction is shown by:
(i) ethane
(ii) ethene?
(c) (i) Write the equation for the complete combustion of ethane.
(ii) Using appropriate catalysts, ethane can be oxidized to an alcohol, an aldehyde and an acid. Name the alcohol, aldehyde and acid formed when ethane is oxidized.
(d) (i) Why is pure acetic acid known as glacial acetic acid?
(ii) What type of compound is formed by the reaction between acetic acid and an alcohol?

Q. The conversion of propene to polypropene is a type of:

1. substitution
2. addition
3. polymerisation
4. combustion

Q.

Which of the following burns by producing a yellow, luminous flame ?
(a) natural gas (b) coke (c) wax (d) charcoal

Q.

Carbon monoxide is a non-combustible gas.

1. True
2. False

Q.

Which of the following pairs are correct?

1. Saturated compounds - yellow flame, Unsaturated compounds - clean or blue flame.

2. Saturated compounds- clean or blue flame, Unsaturated compounds - yellow flame.

3. Saturated compounds and unsaturated compounds both give yellow flame

4. Saturated compounds and unsaturated compounds both give clean or blue flame

Q.

If hydrogen burns in air to produce oxygen, why a rocket which contains hydrogen as fuel produces smoke during its launch?

Q.

While cooking, if the bottom of the utensil is getting blackened on the outside, it means that :
(a) the food is not cooked completely. (b) the fuel is not burning completely.
(c) the fuel is wet (d) the fuel is burning completely.

Q. Which amongst the following compounds can undergo addition reaction?

1. Butyne
2. Propane
3. Butane
4. Ethane

Q.

A hard material X which is mined from the earth is used as a household fuel and also for the generation of electricity at Thermal Power Stations. A soft material Y is also used as a fuel in the form of candles. A gaseous material Z which occurs along with petroleum is increasingly being used as a fuel in running vehicles in its compressed form.
(a) What are the materials, X, Y and Z?
(b) When materials X, Y and Z are burned separately:
(i) Which material burns by producing a yellow, luminous flame?
(ii) Which material ultimately burns without producing a flame?
(iii) Which material can burn in a gas stove by producing a blue flame?

Q.

Which of the following pairs are correct?

1. Saturated Compounds - Yellow Flame, Unsaturated Compounds – Clean or blue Flame

2. Saturated Compounds and Unsaturated Compounds both give yellow flame

3. Saturated Compounds- Clean or blue Flame, Unsaturated Compounds – Yellow Flame

4. Saturated Compounds and Unsaturated Compounds both give Clean or Blue flame

Q.

Oxygen gas helps combustion.

1. True
2. False

Q. Statement 1: Volatile component is responsible for the production of flame.
Statement 2: Gases burn to produce flame.

1. Both the statements are true and statement 2 is the correct explanation of statement 1
2. Both the statements are true and statement 2 is not the correct explanation of statement 1
3. Only statement 1 is true.
4. Only statement 2 is true.

Q.

What is the state of fire?

Q. A substitution reaction of methane is:

1. $C{H}_4+C{l}_2\to CC{l}_4+HCl$
2. $C{H}_4+C{l}_2\to CHC{l}_3+HCl$
3. $C{H}_4+C{l}_2\to C{H}_{3}Cl+HCl$
4. $C{H}_4+C{l}_2\to C{H}_{2}C{l}_2+HCl$

Q. The bottoms of cooking vessels get blackened when used on gas/kerosene stove due to:

1. Incomplete Combustion of fuel
2. Over Combustion of fuel
3. Complete Combustion of fuel
4. None of the above

Q. Which of the following pairs are correct?

1. Saturated compounds - yellow or sooty flame, unsaturated compounds – clean or blue flame.
2. Saturated compounds and unsaturated compounds both give yellow or sooty flame on complete combustion.
3. Saturated compounds - clean or blue flame, unsaturated compounds – yellow flame.
4. Saturated compounds and unsaturated compounds both give clean or blue flame.

Q.

Give one reason that makes liquefied petroleum gas (LPG) a better fuel than kerosene.

Q. Statement 1: Volatile component is responsible for the production of flame.
Statement 2: Gases burn to produce flame.

1. Both the statements are true and statement 2 is the correct explanation of statement 1
2. Both the statements are true and statement 2 is not the correct explanation of statement 1
3. Only statement 1 is true.
4. Only statement 2 is true.