Substitution Reactions are those reactions in which one nucleophile replaces another nucleophile present on a substrate. These reactions can take place via two different mechanism i.e SN¹ or SN². In SN¹ substitution reactions the leaving group leaves first forming a carbocation and nucleophile attacks carbocation in the second step. While in SN² reactions the addition of Nucleophile and leaving of leaving group take place simultaneously.
Example:
OH⁻ + CH₃-Br → CH₃-OH + Br⁻
In above reaction,
OH⁻ = Incoming Nucleophile
CH₃-Br = Substrate
CH₃-OH = Product
Br⁻ = Leaving group
Organic reactions are typically slower than ionic reactions because in organic compounds the covalent bonds are first broken, this breaking of bonds is a slower step, while, in ionic compounds no bond breakage is required as it consists of ions, so only bond formation takes place which is a quicker and fast step.
Answer:
Elements in which the d-sublevel is being filled have the properties of metals
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Answer : The correct option is (c) 
Explanation :
The given balanced chemical reaction is,

From the balanced chemical reaction, we conclude that
As, 3 moles of
react to give 2 mole of 
So, 1 mole of
react to give
moles of 
Thus, the conversion factor needed to convert the number of moles of
to the number of moles of
produced is 
Hence, the correct option is (c) 