Engineering Questions with Answers - Multiple Choice Questions

Applied Chemistry MCQ – Analysis of Coal and Selection

1 - Question

In proximate analysis, which of the following elements can be found?
a) % of moisture content
b) % of carbon
c) % of hydrogen
d) % of nitrogen

View Answer

Answer: a
Explanation: The proximate analysis is also called as quantitative analysis. It is used to find the % of moisture content, volatile matter, ash content and fixed carbon in coal.




2 - Question

From the raw piece, coal is manufactured by ________
a) under crushing
b) over crushing
c) perfectly crushed
d) powdered

View Answer

Answer: c
Explanation: The coal is manufactured by perfectly crushing the raw piece because if the raw material is under crushed and over crushed then the chemical content varies and cannot be good for combustion.




3 - Question

The moisture content in the coal can be given by heating the coal for _____ hours.
a) 2
b) 1
c) 4
d) 6

View Answer

Answer: b
Explanation: To determine the moisture content of the coal, the coal is heated at the temperature 105-1100C in a silica crucible for 1 hour later it is dried, cooled and weighed.




4 - Question

 To find the % of volatile matter in coal, it must be heated in the crucible at ______ temperature.
a) 52610C
b) 32810C
c) 8250C+100C
d) 9250C+200C

View Answer

Answer: d
Explanation: The moisture free coal is taken into a silica crucible and again it is heated at the temperature 9250C+200C for 7 minutes then it is first cooled in air and late in a dessicator.




5 - Question

To calculate the % of ash content the dry coal is heated in ____________
a) blast furnace
b) muffle furnace
c) reverberatory furnace
d) electric furnace

View Answer

Answer: b
Explanation: The ash content is found by heating the moisture less coal in muffle furnace. Reverberatory furnace is a metallurgical or process furnace.




6 - Question

The % of the fixed carbon can be given by _________
a) %C=[loss in weight due to removal of C/weight of coal sample]*100
b) %C=[weight of coal/12*100]
c) %C=100-(% of ash)
d) %C=100-(% of moisture+% of volatile matter+% of ash)

View Answer

Answer: d
Explanation: The % of carbon can be determined easily because the coal will have the highest amount of carbon content. So, from 100 we have to subtract the other contents % to get % of carbon.




7 - Question

High % of moisture is undesirable because _________
a) increases the cost of transport
b) increases the cost of calorific value
c) increases the cost of efficiency
d) decreases the cost of storage cost

View Answer

Answer: a
Explanation: If there is more moisture content in the coal then it is difficult to transport it because the moisture will change into steam.




8 - Question

The moisturizing the coal before introducing into furnace is called as _________
a) moisturizing
b) filtering
c) tempering
d) combustion

View Answer

Answer: c
Explanation: The process of moisturizing the coal is called tempering. Combustion means complete burning. Filtering is the process to remove unwanted contents from the substance.




9 - Question

Ultimate analysis of coal is also called as _________
a) quantitative analysis
b) elementary analysis
c) qualitative analysis
d) secondary analysis

View Answer

Answer: c
Explanation: The ultimate analysis of coal is called as qualitative analysis and the proximate analysis of coal is called as quantitative analysis of coal.




10 - Question

In determination of % of C and H, the coal is burnt in the stream of _______
a) pure sulphur
b) pure nitrogen
c) pure alcohol
d) pure oxygen

View Answer

Answer: d
Explanation: The carbon and hydrogen are burnt in the stream of pure oxygen so that they get converted into CO2 and H2O which are passed through Cacl2 and KOH bulbs.




11 - Question

% of nitrogen can be determined by the process _________
a) dulong’s formula
b) orsat’s apparatus
c) kjeldahl’s method
d) fractional distillation

View Answer

Answer: c
Explanation: The dulong’s formula is used to find calorific value of the coal. Orsat’s apparatus is used for analysis of the flue gas. Fractional distillation is used in purification of petroleum. So, kjeldahl’s process is used for determination of nitrogen.




12 - Question

During metallurgical operations, n2 causes ___________
a) hardness to sample
b) softness to sample
c) moisture to sample
d) heat to sample

View Answer

Answer: a
Explanation: During metallurgical processes, nitrogen causes hardness to the sample, but the presence of nitrogen does not affect the utility of the coal for great extent as it is present in small amounts.




13 - Question

Weight of the coal is 2g and after heating the coal sample, the weight of the coal is 1.82g. What is the % of the moisture in coal?
a) 20%
b) 9%
c) 10%
d) 30%

View Answer

Answer: b
Explanation: We know that % of moisture=[(w1-w2)/weight of coal]*100, where w1=weight of the coal sample, w2=weight of the coal after heating. After substituting the given values in the formula, you’ll get 9% as an answer.
Here’s the calculation step-by-step:
((2 – 1.82) / 2) * 100
==> (0.18/2) * 100
==> 0.09 * 100
==> 9%




14 - Question

Find the % of C from the following data.

% of moisture:10g
% of volatile matter:9.5g
% of ash:11.6g

a) 68.9g
b) 62.1g
c) 63.1g
d) 70.8g

View Answer

Answer: a
Explanation: We know that, % of C=100-(% of moisture+% of volatile matter+% of ash). Use the formula to get the answer 68.9g.




15 - Question

An increase in 1% of percentage of oxygen decreases the calorific value by ________
a) 1.7%
b) 2.7%
c) 3.7%
d) 4.7%

View Answer

Answer: a
Explanation: The increase in 1% of oxygen results in a decrease of 1.7% of calorific value. So, always good fuel must contain less amount of oxygen.

Get weekly updates about new MCQs and other posts by joining 18000+ community of active learners