Question

Why is a Dictionary preferred over a Hashtable in C#?

Answer 1

dictionary called I words group which called I dictionary

dictionary mean words group.

Answer 2

Hashtable is a weakly typed data structure, so you can add keys and values of any object type. When you try to access non existing key Hashtable, it gives null values. Hashtable never maintains an order of the stored values. Hashtable needs boxing/unboxing, so it is slower than Dictionary.