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.
Powerful Sense of Smell. The strongest sense for a shark is their smell. It is a common myth though that sharks can smell blood miles away and then they will find the person or animal that it is coming from. While sharks can smell blood, it often indicates to them that there is wounded prey they can easily overpower. It may surprise you to learn that the nostrils on a shark arenât used for smelling. In fact, they arenât even attached to their mouths. It isnât an instinct of killing that the blood is going to create in them. In fact, if they arenât hungry then they wonât even bother to look for the source of the smell. Some of the species though can smell and indicate even a single drop of blood in the water. This is just an example of how powerful their sense of smell really is.