else condition not called when if condition is false

[Sandz1286]

i was creating a simple guessing game where in the guess is matched to the original string and completes the word.
Encountering 2 errors.
1. When wrong guess is made, the else condition is not called and python returns an error.
Traceback (most recent call last):
File "C:/Users/PycharmProjects/Study2.py", line 12, in <module>
if w.index(x):
ValueError: 'b' is not in list
2. The first letter is not replaced in the guessed word inspite of guessing correctly.

print("=====Hangman =====\nGuess the letters to fill the blanks")

w = ["o", "r", "a", "n", "g", "e"]
b = ["_", "_", "_", "_", "_", "_"]
wrong = 0

while b != w and wrong <=6:
    print(b)
    x = input("Enter your guess:  ")
    if w.index(x):
        i = w.index(x)
        b[i] = x
    else:
        wrong += 1

if wrong == 6:
    print("Your are out of guesses")