Passage V

When rocks are melted at very high temperatures beneath Earth's surface, magma (molten rock) is formed. The gases CO2, and H2O can dissolve in magma. Figure 1 shows, for 4 different magmas (leucitite, basanite, rhyolite, and tholeiitic basalt), how the solubility of CO2 in the magma at 1,150°C varies with pressure (in megapascals MPa).

Figure 2 shows, at 3 different pressures, how the solubility of CO2 in rhyolite magma varies with temperature.

Figure 3 shows, at 4 different pressures, how the solubility of CO2, in rhyolite magma at 750°C varies with the weight percent of H2O in the magma.

30. According to Figure I, at 1,150°C, the solubility of CO2 in basanite magma and the solubility of CO2 in tholeiitic basalt magma are closest in value at which of the following pairs of pressures?

Answer and Explanation

Your Answer is

Correct Answer is J

Explanation

Looking at Figure 1, it is found that the vertical coordinates are the closest when basanite is at 50 MPa and toughiitic basalt is at 100 MPa, so the options F and G are excluded;

When basanite is at 125 MPa and toughiitic basalt is at 250 MPa , the vertical coordinates are also very close, so the option J is reasonable.