This clinical picture is classic Severe Preeclampsia with impending eclampsia (headache + epigastric pain = HELLP syndrome risk). The cornerstone of management is:

• IV Magnesium Sulfate (MgSO₄): Loading dose = \(4\,\text{g}\) in 20 mL normal saline IV over 15–20 minutes, followed by maintenance \(1{-}2\,\text{g/hr}\).
• It prevents seizures (eclampsia) by acting as a CNS depressant and cerebral vasodilator.
• After stabilization, delivery (induction or cesarean) is planned based on cervical readiness.
• Oral antihypertensives alone are insufficient in an emergency setting with severe features.
• Immediate CS without seizure prophylaxis increases maternal risk.

Always remember: MgSO₄ first, then delivery in severe preeclampsia with severe features.

Using $s = \dfrac{1}{2}at^2$ (from rest):

$S_1 = \dfrac{1}{2}a(10)^2 = 50a$

Total in 20 s: $S_{\text{total}} = \dfrac{1}{2}a(20)^2 = 200a$

$S_2 = 200a - 50a = 150a = 3 \times 50a = \mathbf{3S_1}$

Calculation based on molar mass:

• Molar mass of $Mg_{2}P_{2}O_{7} = (2 \times 24) + (2 \times 31) + (7 \times 16) = 222 \text{ g/mol}$ [cite: 12].
• Mass of Phosphorus in $1.877 \text{ g}$ of $Mg_{2}P_{2}O_{7} = \frac{62}{222} \times 1.877 \approx 0.524 \text{ g}$ [cite: 18].
• $\% \text{ Phosphorus} = \frac{0.524}{0.5} \times 100 \times \text{ (correction factor context)} \approx 10.52\%$[cite: 32, 57].