Answer:
The number of moles of AlBr3 = Molarity × Volume
= 0.400 × 0.700
= 0.28 moles
1 mole of AlBr3 gives 3 moles of Br- ions
That is
AlBr3 = Al3+ + 3Br-
Therefore, 0.045 moles of AlBr3 will yield 3 × 0.28 = 0.84 moles
Thus; they are 0.84 moles of bromide ions
