Question

1 mole of hydrogen gas is reacted with 1 mole of iodine vapour. After t
second, 0.8 mole of hydrogen remains. The number of moles of hydrogen
iodide formed at t seconds is
(A) 0.2 (B) 0.4 (C) 0.8 (D) 1.6

Answer 1

first, write the balanced equation:
H2 + I2 --> 2HI
So if 0.2 mol of H2 is used, it produces 0.4 mol of HI. so the answer is B.