MgCl2(aq) is an ionic compound which will have the releasing of 2 Cl⁻ ions ions in water for every molecule of MgCl2 that dissolves.
MgCl2(s) --> Mg+(aq) + 2 Cl⁻(aq)
[Cl⁻] = 0.73 mol MgCl2/1L × 2 mol Cl⁻ / 1 mol MgCl2 = 1.5 M
The answer to this question is [Cl⁻] = 1.5 M
The answer is; C
The radioisotopes in the interior of the earth are not in pure form and have many embedded impurities and are interspersed. Therefore when a neutron is released by a decaying atom, its chances of hitting another radioisotope atom (to continue the chain reaction) are lower than in a manmade nuclear reactor. This way, the radioactive chain reaction in the earth’s interior is not well sustained.
It takes exactly 500 seconds for the sun's radiation to reach the earth or about 8 minutes (8.333333333333... to be exact). Just divide 150 million km by 300,000 km/s. Hope this helps