If the mass of all of the products in a chemical reaction is equal to 100g then the mass of the reactants in that same reaction had to have had a mass of 100g this is due to the law of conservation of matter stating matter cannot be created or destroyed in a chemical reaction.
The answer for the following problem is mentioned below.
- <u><em>Therefore the final volume of the gas is 52.7 ml.</em></u>
Explanation:
Given:
Initial pressure (
) = 290 kPa
Final pressure (
) = 104 kPa
Initial volume (
) = 18.9 ml
To find:
Final volume (
)
We know;
From the ideal gas equation;
P × V = n × R × T
where;
P represents the pressure of the gas
V represents the volume of gas
n represents the no of the moles
R represents the universal gas constant
T represents the temperature of the gas
So;
P × V = constant
P ∝ 
From the above equation;

represents the initial pressure of the gas
represents the final pressure of the gas
represents the initial volume of the gas
represents the final volume of the gas
Substituting the values of the above equation;
= 
= 52.7 ml
<u><em>Therefore the final volume of the gas is 52.7 ml.</em></u>
I think B
STEP-by STEP EXPLANATION
Answer : The correct answer is 1) AlCl₃ - CH₃Cl 2) HNO₃ -H₂SO₄ at room temperature 3) Fuming HNO₃ -H₂SO₄ at 90-100 ⁰ C heat .
I think this reaction is forming 2,4,6- trinitrotoluene from benzene, since the product is not mentioned. Following are the steps to convert Benzene to 2,4,6 trinitrotoluene .
Step 1: Conversion of Benzene to Toluene .
Benzene can be converted to toluene by Friedel Craft Alkylation of benzene . In this reaction reagent AlCl₃ and Ch3Cl is used . Electrophile CH³⁺ is produced which attached on carbon of benzene and formation of Toluene and HCl occur.

Step 2 : Conversion of Toluene to dinitrotoluene.
Dinitritoluene is prepared from toluene by Nitration . This reaction uses Electrophilic substitution mechanism . The reagents used are HNO₃ and H₂SO₄ at room temperature . These reagents produces NO₂⁺ ( nitronium ion ), a electrophile which attacks on C2 and C4 Carbon atoms of Toluene.
Toluene 
Step 3) Conversion of Dinitro toluene to trinitrotoluene.
This reaction is extended nitration of toluene . Further nitration is done in extreme condition . The temperature of reaction is increased to 90- 100 ⁰ C . Due to which there is more production of NO²⁺ ion occurs from HNO₃ -H₂SO₄ and they attack on C6 carbon atom of dinitrotoluene which forms 2,4,6- trinitrotoluene.
Dinitrotoluene 
So over all reaction uses three reagents in order :
