Question

5.) Ripley, a flight officer for the Weyland-Yutani corporation, in the year 2312, landed on the planet LV- 426 where a derelict alien ship was discovered and an alien species was found to have acid for blood. Upon inspection, the pH of the blood was found to be -21. Is the acid strong, what is the [H'], and explain where the "-" comes from? In other words, can Ripley pet the aliens... are they dangerous?

Answer 1

We know that pH = - log[H+] which gives [H+] = 10^-pH.

So at pH = -21, [H+]= 10²¹ which is very high compared to concentration of H+ in strong acids having H+ around 1 M. Thus the acid is strong acid.

The minus sign is due to concentration of H+ being higher than 1 M, as the value -log[H+] becomes negative.

Since the internal body of the alien is very acidic and a slight accidental cut the alien can expose Humans to very dangerous levels of pH of the alien.Thus it not safe to pet the aliens.