Solve the mystery called Chemistry

[nextstopiit]

can u pls explain what is stearic hindrance???

[viny]

Here is a simple meaning of steric hindrance not its definition-


AS the name suggests steric is related to steriochemistry or arrangement of group of atoms in 3D space and hindrance means obstruction......

Whenever bulky or large groups are attached around an atom or group of atoms, they affect the reactivity or decreases the forces of attraction between those atoms and other speceis .....( as in this case reduces the extent of H- bonding)this is steric hindrance....

[bravosiena]

Explain the following:

(i)Why is sulphuric acid not used during the reaction of alcohols with KI?

(II) Why grignard reagent should be prepared in anhydrous conditions?

[chitra]

Here you want nucleophilic substitution reaction. H_2SO_4 is a strong dehydrating agent (H_2SO_4 hydration is thermodynamically favourable) and forms alkene which (elimination) is opposite to what is desired.

[chitra]

The second one:

Grignard reagent can react with water/moisture as follows:

RMgX+H_2O\to RH+HOMgX

If you are preparing Grignard reagent then you do not want it to react as above and get consumed...