Question

1 in a certain titration 10.7 ml of 0 205 M NaOH was consumed to bitrate 20.0 mL of H.SO solution a) White balanced molecular equation of the acid base reaction. 2 pts hi Calculate the moles of NaOH consumed (Show calculations with units at each stage 2 pts and answer with correct sia fig and with units 1 pt) • 200 MOON c) Calculate the moles of H2SO4 present in the sample. (Show calculations with units at each stage 2 pts and answer with correct sig. fig. and with units 1 pt) d) Calculate concentration of H2SO4 in the sample. (Show calculations with units at each stage 2 pts and answer with correct sig. fig. and with units 1 pt) e) What is the color of phenolphthalein indicator in the acid solution? (1 pt) 1) What is the color of phenolphthalein indicator at the equivalence point in the titration (1 pt) 9) After the equivalence point has been reached the phenolophethalein color still slowly disappears over the time. Explain why it occurs? 2 pts

Answer 1

I jumbled up a with b. Please pardon.
9n 1000 mL TIM) NAOH , moles 1000 ml 01205(M) NagH, 1 0.205 0.205 x 19.7. 1000 4.04 x 10-3 0.205 (M) Naul, , em 19.1 ml = Hence: 4.048 10-3 moles of Naoh were consumed 1. 1a) net balanced equation 2NaOH + H₂sou - Na₂SO4 + 2H2O... AS 1 e mole of 4.098 10-3 moles of NaOH Naoh neutralises į moles of H₂ jou; " 1 x 400 x 10-3 moles of но и = 2:02*10-3 moles moles of present 2.02x 10-3 Hasou were in the Thus ; sample

Upl { d on Hasou = 20.0 mL 1000 ml solution, moles of Solution " 2:02x10-3 2:02 x 10-3 x 1000 on 20 2.02 20 lol Hence concentration of Hason : was 0.1101 0.1101(M). (2) In and solution, phenolp thalein was colourless If) At equivalence point, indicator is pink / reddish bink 1g) when phenolpthalein solution is left , ac is absorbed from air, forming carbonic acid in solution, thereby making solution acidic and bleaching the bink color of phenols thalein