Question

Consider if 2.00g of alum were dissolved in water at a neutral pH and then reacted with a slight excess of sodium hydroxide as such:

Al3+ (aq) + 3OH- (aq) ---> Al(OH)3 (s)

What mass of aluminium hydroxide is formed?

Answer 1

1 mole of alum gives 2 moles of Al3+ ion,hence first calculate the moles of alum present in 2 gram then accordingly find the moles of al3+ produced.

Alum has 1 mole of Alum gines amous of A1+3 - a formule of K, S&.ALLS97 2440 To The dissociation of Alum is given by. K SO. Al2(Set) *@**+ 2A1+3+48 014 + 24 ho. .2140 0.00 42 15 mas, = - Mass of Alum moles of Alum 2 gram 474.39 39 glows Motor Mass *3. 0 2 egiem ram of Alum gines 2x0:004.215 moks of Al 0.0084 31 mors. ALT +3 00 of or (Encess A1(04): mok Allon), 0.008 13 moles of A1(04): y 1 mae Alt3 ging 0.00843 mol gine 8 s. Mass produced of Allow? = Moley & Molar Mas = 0.00843 x 78 0,658 gram's :

1 mole Al3+ gives one mole of Al(OH)3 then accordingly calculate the mass of Aluminium hydroxide using its molar mass.