The active ingredient in many laundry bleaches and bleaching powders is
A) hydrogen peroxide, H2O2.
B) hypochlorite ion, ClO-.
C) sodium dichromate, Na2Cr2O7.
D) chlorine, Cl2.
Question 2
The approximate human population of Earth is more than
A) 2 billion.
B) 12 billion.
C) 7 billion.
D) 10 billion.