Question

P+Naoh + H2O = PH3 + NaH2PO2 How to balance it?

Answer 1

`P + 3NaOH + 3H_2O` `->` `PH_3` + `3NaH_2PO_2`

Explanation:

let's say:

`(a)P + (b)NaOH + (c)H_2O` `->` `(d)PH_3` + `(e)NaH_2PO_2`
we can know:
a = d (number of Phosphorus atoms must be the same)
b = e (number of Sodium atoms must be the same)
b + c = 2e (number of Oxygen atoms must be the same)
b + 2c = 3d + 2e (number of Hydrogen atoms must be the same)

and the rest are algebra~ :)

set:
a = d ---(`alpha`)
b = e ---(`beta`)
b + c = 2e ---(`gamma`)
b + 2c = 3d + 2e ---(`delta`)

(`beta`)`->`(`gamma`)
b + c = 2e
e + c = 2e
c = e = b --- (`epsilon`)

(`epsilon`)`->`(`delta`)
b + 2c = 3d + 2e
b + 2b = 3d + 2b
3b = 3d + 2b
b = 3d = 3a --- (`varphi`)

`therefore`
when b = y

then
b = 3a
a = `1/3b`
a = `1/3y`

c = e = b = y

a = d
`1/3y` = d

so the whole equation is going to look like this:
`(1/3y)P + (y)NaOH + (y)H_2O` `->` `(1/3y)PH_3` + `(y)NaH_2PO_2`

multiply 3 both sides:
`(y)P + (3y)NaOH + (3y)H_2O` `->` `(y)PH_3` + `(3y)NaH_2PO_2`

devide y both sides:
`P + 3NaOH + 3H_2O` `->` `PH_3` + `3NaH_2PO_2`
TADA~~~

keep on learning my friend~ hope this helps you~