Consider the following indicators and their ph ranges:
methyl orange 3.2-4.4
methyl red 4.8-6.0
bromothymol blue 6.0-7.6
phenolphthalein 8.2-10.0
alizarin yellow 10.1-12.0
assume an indicator works best when the equivalence point of a titration comes in the middle of the indicator range. for which of the following titrations would methyl red be the best indicator?
a) 0.100m hno3+0.100m koh.
b) 0.100m aniline(kb=3.8×10^-10)+0.100m hcl.
c) 0.100m nh3(kb=1.8×10^-5)+0.100m hcl.
d) 0.100m hf(ka=7.2×10^-4)+0.100m naoh.
e) 0.100m acetic acid(ka=1.8×10^-5)+0.100m naoh.

Straightforward questions answered in the powerpoint slidesreaction: heating the starting materials under refluxwhat does it mean to heat under reflux? why do we choose water as the reflux solvent? what are boiling chips used for? why do we put a condenser on top of the reaction? why do we add heat and let the reaction stir for 30 minutes? why do we add sulfuric acid to the reaction after it cools as opposed to when it’s still hot? separation: filtration of precipitatewhy don’t we do an aqueous and organic extraction in the separatory funnel? why do you rinse the salicylic acid on the filter with ice cold water? purification: recrystallization of salicylic acid (no hot filtration needed)what is the difference in the amount of room temperature water vs. boiling water needed to dissolve the salicylic acid (assume a 1.2 gram yield of salicylic acid)? remember, in the lab if you need x ml of boiling water to dissolve a solid, then you should add a little more (definitely no more than 1.5 times the theoretical amount) to ensure it doesn’t recrystallize prematurely. analysis: melting point of salicylic acidwhat can you conclude if the melting point of the salicylic acid you just synthesized is 152-155oc and the 1: 1 mix of your product and “synthetic” salicylic acid is 151-154oc?