Question

Difference between lexical and syntax analysis

Answer 1

Lexical analyser divides the input into valid tokens i.e smaller entities which make sense and are well defined in the language:

For example - "beautiful" is a valid token as it is a valid word in English.
Whereas "dsefuewfiu" is not a valid token as it does not make any sense.

Whereas Parser checks for the grammar i.e the sentence adheres to the laws of sentence formation in English:

For example- "My name is Rahul" is a valid English sentence.
Whereas "name my is Rahul" makes no sense.


This is the basic difference between a lexical analyzer and parser

Answer 2

Lexical analysis is the first phase of a compiler. It takes the modified source code from language pre processors that are written in the form of sentences. 
A syntax analyzer or parser takes the input from a lexical analyzer in the form of token streams.