Answer:
0.218mol
Step-by-step explanation:
Using Avogadro's law equation;
Va/na = Vb/nb
Where;
Va = volume of gas A
Vb = volume of gas B
na = number of moles of gas A
nb = number of moles of gas B
According to the information in this question,
na = 0.4mol
nb = x mol
Va = 220ml
Vb = 120ml
Using Va/na = Vb/nb
220/0.4 = 120/x
Cross multiply
0.4 × 120 = 220 × x
48 = 220x
x = 48/220
x = 0.218mol