For chemistry students · 4 minute read
What happens when mercury(II) chloride and sodium hydroxide react?
Mercury(II) chloride and sodium hydroxide form yellow mercury(II) oxide in the supported overall equation.
- Balanced equation
- HgCl2(aq) + 2NaOH(aq) -> HgO(s) + 2NaCl(aq) + H2O(l)
- Model and safety boundary
- This is virtual-only outside a specialist mercury laboratory. The model does not estimate exposure or waste risk.
Your study goal: Balance the overall equation and explain why the represented solid is HgO.
Open the prepared exampleThe exact supported pair opens in a beaker. Nothing runs until you select Analyze.
Supported prediction
HgCl2(aq) + 2NaOH(aq) -> HgO(s) + 2NaCl(aq) + H2O(l)
What the equation means
Under specialist mercury controls, dilute mercury(II) chloride and sodium hydroxide form yellow mercury(II) oxide, sodium chloride, and water. An initially formed mercury hydroxide is unstable and is represented by mercury(II) oxide in the balanced overall equation.
Expected observation
The supported result represents a yellow HgO precipitate
The supported result represents a yellow HgO precipitate. Color and amount are simplified cues, not measurements.
Read the equation
Three details that explain the result
Connect the coefficients and formulas to the gas, solution, and visible cue.
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Count the hydroxide
Two NaOH units provide enough oxygen and hydrogen for HgO and H2O in the overall equation.
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Balance the chloride
Two chloride ions from HgCl2 remain with two sodium ions as 2NaCl(aq).
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Name the solid
Mercury hydroxide is unstable here. The fixed overall equation represents the solid as HgO(s).
Three safety notes
Read these before any physical experiment
- 01
Treat this as virtual-only outside a specialist mercury laboratory.
- 02
Avoid all skin contact, ingestion, and inhalation of mercury materials.
- 03
Collect the entire mixture as mercury-containing hazardous waste.
Common questions
What students usually ask next
Use these distinctions to move from the visible reaction to the particle-level explanation.
Why is the product HgO rather than Hg(OH)2?
The supported overall equation represents unstable mercury hydroxide through its oxide and water products.
Can this be tried as a home experiment?
No. Mercury compounds are highly hazardous and require specialist controls and hazardous-waste handling.
Keep exploring
Connect this observation to another reaction
These guides use the same pattern: predict the equation, identify the visible cue, then check what the virtual model leaves out.
See how the full virtual lab works