Which of the following is the correct chemical formula for magnesium hydrogen carbonate?

• A. MgCO3
• B. Mg(HCO3)
• C. Mg2CO3
• D. Mg(HCO3)2

Answer: (D)

Verified step by step guidance

1. Understand the composition of magnesium hydrogen carbonate: it consists of magnesium ions (Mg^{2+}) and hydrogen carbonate ions (HCO_3^{-}).
2. Recall the charges of the ions involved: magnesium ion has a charge of +2, and hydrogen carbonate ion has a charge of -1.
3. To write the correct formula, balance the total positive and negative charges so the compound is electrically neutral.
4. Since magnesium has a +2 charge and hydrogen carbonate has a -1 charge, two hydrogen carbonate ions are needed to balance one magnesium ion.
5. Combine the ions accordingly to write the formula as \(Mg(HCO_3)_2\), indicating one magnesium ion and two hydrogen carbonate ions.