Please help me

Question

PCl5 + H2O → H3PO4 + HCl

What coefficients will balance the equation?

1, 4, 1, 5
1, 5, 1, 1
2, 5, 1, 2
2, 4, 2, 5

And

NH4OH(aq) → H2O(l) + NH3(g)

What coefficients will balance the equation?

1, 2, 2
3, 3, 4
2, 1, 2
1, 1, 1

I think the second question is 212 but not sure I really need help

Answer 1

I'm not a chemist by profession so I found this on the Internet.

I think these are the solutions, at least the best that can be found on the Internet.

The law of conservation of mass states that no atoms can be created or destroyed in a chemical reaction. The number of atoms in the reactants has to balance the number of atoms in the products.

Compare the number of atoms for each element on both sides of the equation, change the coefficient so the number is the same.

PCl₅ + H₂O→H₃PO₄ + HCl

​P is balanced becouse you have 1 P atom on left side and 1 P atom on right side.

To​ balance Cl multiply HCl by 5.

PCl₅ + H₂O→H₃PO₄ + 5 HCl

Cl is balanced becouse you have 5 Cl atom on left side and 5 Cl atom on right side.

To balance H multiply H₂O by 4.

PCl₅ + 4 H₂O→H₃PO₄ + 5 HCl

H is balanced becouse you have 4 H atom on left side and 3 + 1 = 4 H atom on right side.

O is balanced becouse you have 4 O atom on left side and 4 O atom on right side.

So:

PCl₅ + 4 H₅O→H₃PO₄ + 5 HCl

Solution:

1 , 4 , 1 , 5

Balance reaction algebraicly:

Add unknown coefficients to all molecules.

u PCl₅ + v H₂O→ w H₃PO₄ + t HCl

Create system of equations to find the coefficients.

To balance P:

u = w

To balance Cl:

5u = t

To balance H:

2 v = 3 w + t

To balance O:

v = 4 w

Now you have system of equations:

u = w

5 u = t

2 v = 3 w + t

v = 4 w

The solutions are:

t = 5 , v = 4 , w = 1, u = 1

1 ∙ PCl₅ + 4 ∙ H₂O→ 1 ∙ H₃PO₄ + 5 ∙ HCl

Solution:

1 , 4 , 1 , 5

Similarly:

NH₄OH→ H₂O + NH₃

Solution:

1 , 1 , 1

​Balance reaction algebraicly:

Add unknown coefficients to all molecules.

u NH₄OH→ v H₂O + w NH₃

Create system of equations to find the coefficients

To balance N:

u = w

To balance H:

5u = 2 v + 3 w

To balance O:

u = v

Now you have system of equations:

u = w

5 u = 2v + 3 w

u = v

The solutions are:

v = 1 , w = 1, u = 1

1 ∙ NH₄OH→ 1 ∙ H₂O + 1 ∙ NH₃

Solution:

1 , 1 , 1