5 20 pts Write net ionic equations describing the reactions

5. (20 pts) Write net ionic equations describing the reactions that occur when equimolar amounts of the following species are mixed in water. Is the pH greater than, equal to, or less than 7? (Note: use your acid/base table) (a) HBr, NaHCO (b) Cr(SO4) (c) HNO2, CsOH (d) HCIO4, RbOH

Solution

a)

net ionic equation:

H+ (aq) + HCO3- (aq) -----------------> H2O (l) + CO2 (g)

pH is less than 7 becuae it is acidic solution

b)

net ionic equation:

2Cr+3 (aq) + 6 H2O (l) --------------------> 2Cr(OH)3 (s) + 6H+ (aq)

it is also acidic pH <7

c)

net ionic equation:

HNO2 (aq) + OH- (aq) ----------------------> NO2- (aq) + H2O (l)

solution is basic . pH > 7

d)

net ionic equation:   H+ (aq) + OH- (aq) ---------------------> H2O (l)

pH = 7. so solution is neutral