What is the role of phenolphthalein in a titration? It makes the solution acidic

Question

What is the role of phenolphthalein in a titration? It makes the solution acidic. It is an indicator that changes from colorless to pink when a solution becomes acidic. Both A and B are correct. It is an indicator that changes from colorless to pink when a solution becomes basic. It makes the solution basic. Given the data below, find lattice energy for Na_2O, Which is the delta H degree for the following reaction: 4880 kJ/mol 4630 kj/mol 4134 kJ/mol -345.7 kj/mol 4530 kJ/mol A student performed a titration of acetic acid with sodium hydroxide and observed the molarity of the basic solution to be 0.2324M. The correct molarity of the solution is 0.2112M. What is their percentage error? 2.120% 9.122% 21.20% 90.88% 10.03%

Explanation / Answer

12. d (as indicator)

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13.

The reaction is : 2Na+ (g) + 1/2 O- (g) ---> Na2O

So, from the last value given (-2488kJ/mol) u need to convert Na(s)----> Na(g) and then ioniza Na(g) ----> Na+ (g)

Also, need to convert O2---> 2O and O---> O2-

Laatice energy = -2488 kJ/mol - [2*100.02 + 2*495.8 +1/2(498.36) + (-142.5+844)] = 345.7kJ/mol

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% error = [ I 0.2112-0.2324 I/0.2112 ] *100 = 10.03%

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