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

A patient was diagnosed with some ailment. He was given five different tablets to take at night at an interval of 15 minutes.

How long will it take the patient to consume all the five tablets?

I have holes on the top and bottom. I have holes on my left and on my right. And I have holes in the middle, yet I still hold water. What am I?

It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?

John leaves home and then he takes three right turns. John wants to return to home but he was scared of Jacob, who is wearing a mask.

What is John Situation ?

The more it dries, the wetter it becomes. Can you tell what it is?

I have a mouth but I don't eat.
I have a bank but have no money.
I have a bed but i dont sleep.
I wave but have no hands.

Who Am I ?

I am the black child of a white father, a wingless bird, flying even to the clouds of heaven. I give birth to tears of mourning in pupils that meet me, even though there is no cause for grief, and at once on my birth, I am dissolved into air. What am I?

Can you solve the tricky chess rebus puzzle below by ciphering the hidden meaning?

You can see it everyday, But cannot touch it at will. What is it?