Answer:
Fossil fuels are hydrocarbons, primarily coal, fuel oil, or natural gas, formed from the remains of dead plants and animals. In common dialogue, the term fossil fuel also includes hydrocarbon-containing natural resources that are not derived from animal or plant sources.
Explanation:
fossil fuels are continually formed by natural processes, they are generally classified as non-renewable resources because they take millions of years to form, and known viable reserves are being depleted much faster than new ones are generated.
It is the third one this is simple
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 :

<u>Answer:</u> The concentration of reactant after the given time is 0.0205 M
<u>Explanation:</u>
Rate law expression for first order kinetics is given by the equation:
![k=\frac{2.303}{t}\log\frac{[A_o]}{[A]}](https://tex.z-dn.net/?f=k%3D%5Cfrac%7B2.303%7D%7Bt%7D%5Clog%5Cfrac%7B%5BA_o%5D%7D%7B%5BA%5D%7D)
where,
k = rate constant = 
t = time taken for decay process = 11.0 min = 660 s (Conversion factor: 1 min = 60 s)
= initial amount of the reactant = 0.400 M
[A] = amount left after decay process = ?
Putting values in above equation, we get:
![4.50\times 10^{-3}s^{-1}=\frac{2.303}{660s}\log\frac{0.400}{[A]}](https://tex.z-dn.net/?f=4.50%5Ctimes%2010%5E%7B-3%7Ds%5E%7B-1%7D%3D%5Cfrac%7B2.303%7D%7B660s%7D%5Clog%5Cfrac%7B0.400%7D%7B%5BA%5D%7D)
![[A]=0.0205M](https://tex.z-dn.net/?f=%5BA%5D%3D0.0205M)
Hence, the concentration of reactant after the given time is 0.0205 M
This is due to the different properties of the depth of the earth. The interior of the earth is made of heavier metals such as nickel and is hotter than the upper layers. The great pressure in these deep depths keep the elements from melting even at very high temperatures. The upper layers are made up of lighter elements such as iron and magnesium - and are less dense. These layers experience less pressure and temperatures than the deep interiors. Therefore their properties is a bit different. This also allows these layers to be semi-plastic than the soil core.