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: Identify the primary components of sea salt. Seawater's average salinity is roughly 3.5% (35 parts per thousand). This salinity arises from various dissolved ions.

Step 2: Rank the major salts by their prevalence. The most prevalent salts, derived from the major ions, are listed below, from most to least abundant: 1. Sodium chloride (NaCl) - Significantly the most abundant, constituting 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\(_4\), mentioned in the original question, is a trace element and likely a typo; it should be Calcium sulfate).

Step 3: Construct the sequence using the provided letters. The order from highest to lowest abundance is: D (NaCl) \(\rightarrow\) A (MgCl\(_2\)) \(\rightarrow\) C (MgSO\(_4\)) \(\rightarrow\) B (CaSO\(_4\)). The sequence is D, A, C, B.