I am having trouble understanding how to come up with the products for single replacement reactions. Can any one check my work and tell me what i am doing, and also point out if i am missing any rules.

Question

1. KI + Cl2 --->
2. Fe + HCl --->
3. Zn + HNO3 --->

For number 1 i came up with
2KI + Cl2 ---> 2KCl + I2
Correct answer is KCl + I2 <- now in that shouldn't chlorine be 2 to balance it out?

For number 2 i came up with
Fe + HCl ---> H2 + FeCl
Correct answer is
2 Fe + 6 HCl ---> 2 FeCl3 + 3 H2
How did Cl get 3 atoms on right.. completely lost on this one

For number 3 i came up with
2 Zn + 2HNO3 --> H2 + 2ZnNO3
Correct answer is
Zn + 2HNO3 --> Zn(NO3)2 + H2

Answer 1

You have #1 correct.
#2. Fe is +3 oxidation start (valence) so the formula for iron chloride is FeCl3. Then you balance it as the answer shows.

#3. Same problem. Zn has oxidation state (valence) of +2; therefore, zinc nitrate is Zn(NO3)2 and you balance from there.