How does the solubility of atmospheric carbon dioxide change with variations in pH and salinity?

Decreasing pH decreases the solubility; increasing salinity increases the salinity.

Explanation:

Atmospheric carbon dioxide in seawater is involved in the following equilibria:

(i)   CO₂(g) ⇌ CO₂(aq)

(ii)  CO₂(aq) + H₂O ⇌ H₂CO₃(aq)  

(iii) H₂CO₃(aq) + H₂O(l) ⇌ H₃O⁺(aq) + HCO₃⁻(aq)  

(iv) HCO₃⁻(aq)+ H₂O(l) ⇌ H₃O⁺(aq) + CO₃²⁻(aq)

1. Effect of pH  

Decreasing pH increases [H₃O⁺].

According to Le Châtelier's Principle, the position of equilibrium of (iv) will be pushed to the left.  

This, in turn, pushes the positions of equilibrium of (iii), (ii), and (i) to the left.

The net effect is that CO₂ is pushed out of the solution and back into the atmosphere.

Thus, decreasing the pH decreases the solubility of atmospheric CO₂.

2. Effect of salinity

Salinity includes the measurement of all ions in seawater, not just Na⁺ and Cl⁻.

An important ion that contributes to salinity is Ca²⁺.

Ca²⁺ ions are involved in the equilibrium  

Ca²⁺(aq) + CO₃²⁻(aq) ⇌ CaCO₃(s).

Thus, increasing the salinity ([Ca²⁺]) removes CO₃²⁻ from the solution and pulls the position of equilibrium of (iv) to the right.

The effect goes back through the chain of equilibria.

The net result is that more atmospheric CO₂(g) dissolves in the seawater to replace the CO₃²⁻ that has been removed.

Increasing the salinity increases the solubility of atmospheric CO₂.

most historians agree that gabriel mouton, the vicar of st. paul’s church in lyons, france, is the “founding father” of the metric system. he proposed a decimal system of measurement in 1670. mouton based it on the length of one minute of arc of a great circle of the earth (now called a nautical mile, 1852 meters). he also proposed the swing-length of a pendulum with a frequency of one beat per second as the unit of length (about 25 cm). a pendulum beating with this length would have been fairly easy to produce, thus facilitating the widespread distribution of uniform standards. over the years, his work was revised, improved, and extended by a number of french scientists.

the political sponsor of weights and measures reform in the french revolutionary national assembly was the bishop of autun, better known as talleyrand. under his auspices, the french academy appointed several committees to carry out the work of developing a usable system of weights and measures for france. one of the committees recommended a decimalized measurement system based upon a length equal to one ten-millionth of the length of a quadrant of the earth’s meridian (i.e., one ten-millionth of the distance between the equator and the north pole).

substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.