Answer
30mL of 0.15M K2CrO4 has more K+ ions
Work Step by Step
The first solution is 30mL of 0.15M K2CrO4. First off, we find how many moles of K2CrO4 we have as follows:
30mL * ( 1L/1000mL) = 0.030 L
0.15M = 0.15mol/L * (0.030L) = 0.0045 mol K2CrO4
Then we see that in K2CrO4 there are 2 moles of K+ for each mole of K2CrO4 so
0.0045 mol K2CrO4 * (2 mol K+/1 mol K2CrO4) = 0.009 mole K+
The second solution is 25mL of 0.080 M K3PO4
Here again 25mL --> 0.025L
0.080 mol/L * 0.025L = 0.002 mole K3PO4
Last, there are 3 moles of K+ for each mole of K3PO4 so we have
0.002 mole K3PO4 * (3 moles K+/1mole K3PO4) = 0.006 moles K+
Since 0.009 > 0.006 then solution 1 has more
