2008 General Studies, all questions
UPSC Prelims 2008 · General Studies
Question 36: Science and Technology
What is the pH level of blood of a normal person?
a4·5 – 4·6
b6·45 – 6·55
c7·35 – 7·45
d8·25 – 8·35
AnswerThe answer is (c).
Normal human blood is slightly alkaline, with a pH between 7.35 and 7.45. The body holds it in this narrow band through buffers such as bicarbonate, and through the lungs and kidneys. A fall below 7.35 is acidosis and a rise above 7.45 is alkalosis; either is dangerous. Values near 4.5 or 6.5 are acidic, and 8.3 is too alkaline for life.
Why each option is right or wrong
- (a) pH 4.5 to 4.6 is strongly acidic and incompatible with life.
- (b) pH 6.45 to 6.55 is acidic; blood is slightly alkaline.
- (c) The normal range for blood is 7.35 to 7.45.
- (d) pH 8.25 to 8.35 is far too alkaline for blood.
Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2008, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.