Explanation
Meta directing deactivators< Ortho-Para directing deactivators (halogens) < Ortho -Para directing Activators
*Activator -An atom or molecule capable of increasing electron density on benzene ring either by hyper conjugation or by mesomeric effect +R .
* Halogen are dectivator due -I effect so their reactivity is less than of benzene but Ortho-Para directing due to +R mesomeric effect.
*Deactivates decreases electron density on benzene ring so electrophile can attack on meta position with difficulty.
Now the order
(Meta directing deactivators)
$$-NO_2< -CN < -SO_3H < -COCH3 <-COOH < - COOCH_3 < -COH <$$
( OP deactivator)
$$-I < - Br < -Cl < -F <$$
(OP activators )
$$-H < -ph < -CH_3 < -COCH_3 < -N(CH_3)_3 < -OH < -NH_2$$
Hence option A $$-OH$$ is a correct answer.
Hint: If an iodine group is attached to a compound then in IUPAC name $$iodo$$ will come.
Explanation:
The structure of tertiary butyl iodide is-
The longest chain of the compound is of $$3$$ carbon so the prefix is $$propane$$
The compound has an Iodine group and a methyl group at $$C-2$$ position as a substituent so it would $$2-Iodo-2-methyl$$$Its IUPAC name is – $$\text{2-iodo-2-methyl propane}$$.
Correct Option: $$D$$
Rules for Naming Hydrocarbons:-
Rule-I Selection of the longest carbon chain.
Rule-II Numbering the longest chain: Longest chain is numbered starting from a terminal carbon. Numbering is done is such a way that lowest possible number is given to the side chain or a functional group.
Rule-III Writing names of branched, saturated hydrocarbons, locants are written first in alphabetical order followed by name of parent chain.
Rule-IV Some common names are retained in $$IUPAC$$ system for unsubstituted hydrocarbon only.
Order of numbering:- $$-CHO>-OH$$ (preference)
(Refer to Image)
$$\longrightarrow$$ Ring is $$5$$ membered.
$$\longrightarrow$$ functional group is aldehyde.
$$\longrightarrow$$ at $$2^{nd}$$ position $$-OH$$ group.
So, the name of the given compound is $$2-hydroxy$$ $$cyclopentan-1-al$$.
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