Question

Arrange the following significant salts in decreasing order of their percentage in the oceans:
A. MgCl\(_2\)
B. CaSO\(_4\) (assuming typo for CuSO\(_4\))
C. MgSO\(_4\)
D. NaCl

• A. D, B, C, A
• B. D, A, C, B
• C. D, C, A, B
• D. D, B, A, C

Hint:

Just remember that seawater is overwhelmingly just salty water, so Sodium Chloride (NaCl) will always be first. The next most common positive and negative ions are Magnesium (Mg\(^{2+}\)) and Sulfate (SO\(_4^{2-}\)), which combine with others to form the next most abundant salts.

Answer 1

The Correct Option is B

Step 1: Recall the major components of sea salt.
Seawater has an average salinity of about 3.5%, meaning 35 parts per thousand. This dissolved salt is composed of several different ions.

Step 2: List the major salts by their abundance.
The most common salts, formed from the major ions, are listed below in order of decreasing abundance: 1. Sodium chloride (NaCl) - By far the most abundant, making up over 77% of sea salt. 2. Magnesium chloride (MgCl\(_2\)) - The second most abundant. 3. Magnesium sulfate (MgSO\(_4\)) - The third most abundant. 4. Calcium sulfate (CaSO\(_4\)) - The fourth most abundant. (Note: Copper sulfate, CuSO\(_4\), as written in the original question, is a trace component at best and is considered a typo for Calcium sulfate).

Step 3: Form the sequence based on the given letters. The order from most abundant to least abundant is: D (NaCl) \(\rightarrow\) A (MgCl\(_2\)) \(\rightarrow\) C (MgSO\(_4\)) \(\rightarrow\) B (CaSO\(_4\)). The sequence is D, A, C, B.