What is the hydrogen ion concentration of a solution with a pH of 4.2? a) 3.2 x 10-6 M
b) 2.7 x 10-9M
c) 6.4 x 10-5 M
d) 1.0 x 10-6 M.

40 points. given: two congruent angles ∠c and ∠r are supplementary. prove: ∠r and ∠c are both right angles. it doesn't have to be exactly 10 rows.statements reasons1. 1. 2. 2. 3. 3. 4. 4. 5. 5. 6. 6. 7. 7. 8. 8. 9. 9. 10. 10.