根据题意,大略步骤如下.
【由I2为C作为着眼点】
2HI(g) ------- H2(g)+ I2(g)
1 2 1
2c 2c c
4PH3(g) ------- P4(g)+ 6H2(g)
4 1 6
2/3(d-2c) 1/6(d-2c) d-2c
PH4I(s)-------- PH3(g)+ HI(g)
1 1
b+2c b+2c
所以,n(p4)= 1/6(d-2c)
n(ph3)= (b+2c)-2/3(d-2c)
=b+ (10/3)c - 2/3(d)