2-Chloro-3,3-dimethylbutane or 3-Chloro-2,2-dimethylbutane...

My teacher first one is correct but why is the second one not correct in terms of locant rule ?? Pls help

PICTURE ATTACHED-

The correct name of the above compound is –; 2-Chloro-3,3-dimethylbutane
ThIs IUPAC name is correct because as per the rule when different substituents are present ,then numbering is done in such a way that substituent which comes first in the alphabetical order should gets lower number.Since in alphabetical order chloro comes first than methyl therefore the above compund is named as 2-Chloro-3,3-dimethylbutane and not 3-Chloro-2,2-dimethylbutane.As in such naming chloro gets lower number 2 and not 3.

Dear student i have already explain this to you.Again understand this -- This compound has three substituents two methyls and one chlorine.Now according to IUPAC nomenclature,first select the longest chain which is of four carbon atoms and numbering of these side chain substituents should be done in alphabatical order.Since chloro comes first than methyl therefore we have to number the chloro in such a way that it gets lower number than methyl.So we are numbering it as 2 and methyls as 3,3 because both on third carbon atom and thus its name will be 2-Chloro-3,3-dimethylbutane,which is correct IUPAC name.First this rule of alphabetical order is applied.Although in such naming you might be thinking that lowest locant rule gets violated,but order of naming a compound follows a set of rules in which alphabatical order is followed and then numbering is done.Hope i am able to clear your doubt.
Besides this i would like to advice you to practice more and more question of IUPAC naming because it will give you wide range of questions and you will learn how to name the organic compounds.First read all the rules given by the IUPAC in sequence wise and then move to the questions.All the very best i am sure you will get command over this.