Is it right to say that the width of int data type depends on the data width of the ALU ? For example is it right to say that a 32-bit processor will have int data type as 32-bit wide? Similarly for 16 bit and 8 bit(please note that C guarantees that the size of int at least greater than 16 bit).
No, this is up to the implementation. For instance, many compilers for 64bit systems have 32bit wide ints still.