When 100mL of HCl are added, the pH of the solution will equal 7. Bromthymol Blue, an indicator which changes color in the 6-8 pH range is used in this case, because we can see when the pH is equal to 7.
Firstly, you have more chance of getting hit by a car or killed by a coconut falling on your head than getting attacked by a shark. A shark isn't going to pick you by what colour your boogie board is. Usually they attack people who have just gone to the toilet or are simply the unlucky ones. I think Mythbusters found that sharks are not attracted to certain colours but they tend to bite the colour yellow more once they do attack.
, I dive with sharks everyday! Many people that find out I dive with sharks on a daily basis ask me this question with horror and concern written all over their face. No, menstration blood does not attract sharks. This is because they're only stimulated by the blood of fish (especially fatty ones such as tuna). They're more attracted to the vibrations and sounds that we make while splashing on the surface of the water, or while diving.