There are are five things wrong with this sentence; only geniuses will be able to to spot all of the mitstakes

Can anyone tell me a word in the English dictionary which has a silent 'z'?

A wooden log balances equally on the scales when weighed with three-quarters of a pound and three-quarters of a wooden log.

Can you calculate the weight of the entire wooden log?

Find The Next Number in this series.
1, 2, 6, 42, 1806 ?

There are people and strange monkeys on this island, and you can not tell who is who (Edit: until you understand what they said - see below). They speak either only the truth or only lies.
Who are the following two guys?
A: B is a lying monkey. I am human.
B: A is telling the truth.

See the given image carefully. What you have to do is move the blue checkers in the position of the black checkers and vice versa. You are only allowed to move the checker to an adjacent empty space. Do it in the least possible moves.

There is one thing that goes round the house and also inside the house but never even share a brief touch. What is it?

Decode below rebus
D
N
A
T
S , D

Analyze and find the missing item in the sequence:
16, 06, 68, 88, __, 98

Here is a conversation between a couple who both are software professionals.

Husband: Hey! What is your date of birth?
Wife Replied Angrily: It is 591062400
Husband after doing some calculations replied, "Got It".

What is the DOB of the wife?