Identify the correct statements among the following a) C ₆₀ molecule has 12 six-membered rings and 20 five-membered rings b) H ₂ CO ₃ / HCO ₃⁻ buffer system helps to maintain pH of blood between 7.26 and 7.42 c) Graphite is used as a dry lubricant in machines running at high temperatures

Step-by-step solution

- a) (C₆₀ ) molecule has 12 six-membered rings and 20 five-membered rings. This is incorrect. The (C₆₀ ) fullerene molecule, also known as buckminsterfullerene, has a spherical structure with 12 five-membered rings and 20 six-membered rings. - b) ( H ₂ CO ₃ / HCO ₃⁻ ) buffer system helps to maintain pH of blood between 7.26 and 7.42. This is correct. The carbonic acid-bicarbonate buffer system is a crucial component of blood plasma that resists changes in pH, keeping it within a narrow range required for proper phy