Answer:
4.48 - 6.48
Explanation:
A pH indicator works in a better way in a range of pH = pKa ± 1. That means we need to determine the pKa of the indicator propyl red to find the range over which it change its color. That is:
pKa = -log Ka
pKa = -log 3.3x10⁻⁶
pKa = 5.48
That means the range over propyl red will change from yellow to red or vice versa is:
4.48 - 6.48
<u>Answer:</u>
A reaction is said to occur if there is a formation of an insoluble solid or a precipitate(s) or a liquid (l) or a gas(g).
If both the reactants and products are in aqueous state, No reaction takes place.

All chlorides and Bromides are soluble except that of Ag, Hg and Pb.
Hence, No reaction takes place since all the reactants and products are in aqueous states.

Salts of Group IA are soluble. Hence No reaction takes place

(REACTION TAKES PLACE)
All hydroxides are insoluble except that of Group IA, ammonium ion and Group IIA down from Calcium.
Hence Reaction takes place with the formation of
precipitate
A firework exploding is a chemical change as soon as you light the fuse the combustion reacts with the gunpowder.
I hope this helps, good luck!!!!