Answer:
There is one single covalent bond between two carbon atoms.
Explanation:
We know that sharing of electrons form covalent bonds.
If we look upon K,L,M ,N shells of the carbon and hydrogen atoms.
We found that Hydrogen is having only 
electron in K shell.
And Carbon on the other hand is having 
electrons in K shell and 
electrons in L shell.
So carbon have valence electrons,and it can share bonds with any relevant atom to complete its octet.
And Hydrogen requires electron to complete its doublet.
Alkane general formula 
For ethane 
Carbon atom is shared by 
Hydrogen.
The remaining one electron 
of carbon will be shared with another carbon atom.
An image of the sharing of electrons attached below,
Hence we have only covalent bond between the two.
Answer:
Valence electrons or outer electrons are most important as they participate in bonding. The octet rule states that atoms gain, lose, or share valence electrons to have filled energy levels.. this gives atoms a stable configuration like that of the nearest noble gas.
1. This is a combustion reaction.<span>
<span>Combustion reactions can happen with the </span>presence of O</span>₂ <span>gas. O₂<span>
reacts with another element or compound and </span></span>oxidize<span> it. Here ethanol reacts with O₂<span> and produces </span></span>CO₂ and H₂O as products.<span> <span>Combustion is also called as </span></span>burning. <span>
2.
Reaction will shift to right. <span>
</span><span>If more CH</span>₃CH₂OH is added to the system, then the</span> amount of CH₃CH₂OH will increase.<span> <span>Then the equilibrium in the system </span></span>will be broken.<span> <span>To make the equilibrium again, the </span></span>added CH₃CH₂OH should be removed.<span> To do that system will consume more CH</span>₃CH₂<span>OH to make products which helps to decrease
the amount of ethanol. Hence,
the reaction will shift to right.<span>
3. The reaction
will shift to right.</span><span>
</span><span>If the water is extracted from the system, the </span>amount of water will decrease. <span>That means the </span>amount of products decrease. Then the system will try to gain equilibrium by increasing the water. To increase water the forward reaction should be enhanced. <span>Hence, the</span> reaction will shift to right.<span>
4. The reaction
will shift to right.
</span><span>This is an </span>exothermic reaction <span>since it </span>produces heat. If the produced heat is removed, then the system will be cold. To maintain the temperature, system has to increase the amount of heat produced. Then, the forward reaction should be
enhanced. Hence, the reaction
will shift to right.<span>
5. The Le
Chatelier's principle.
</span>Le Chatelier's principle says if a
condition changes in a system which was in an equilibrium state, the system
will try to gain equilibrium by correcting the changed condition back to
normal. Most of industries which make
chemicals use this principle</span>
