SCIENCE · INVESTIGATE AND EXPLAIN

Construct conjugates without confusing H⁺ with H

Build donor and acceptor products, test charge changes and distinguish globally balanced candidates from a proton transfer.

Learning outcome: Construct conjugate acid/base compositions and charges, explain a conserved-total counterexample and represent an amphiprotic species in both roles.

Starting recap

A proton transfer moves a hydrogen nucleus with charge +1 and no electrons. The donor becomes its conjugate base; the acceptor becomes its conjugate acid.

All lessons are open directly. Your saved experiments remain when you leave and return.

Try

Removing one H from HF and adding one H to water while leaving both charges unchanged conserves total H and total charge—but is not the specified H⁺ transfer.

Open the experiment

Predict

Predict each product charge and each species electron count before selecting changes. Predict whether balanced global totals alone establish a proton-transfer event.

Your prediction and reason

Experiment

Inspect the initial hydrogen-only proposal, then repair both charge changes. Try no changes and one-sided edits. Construct ammonium donation and water-to-ammonia transfer; identify conjugate pairs. Compare bicarbonate as donor and acceptor and capture both representations.

Construct the two conjugates of a proton transfer

Learner conjugate construction · species accounting · Original symbolic construction of a single H⁺ transfer. Donor/acceptor roles and candidate parent identities are supplied; global atom and charge totals are insufficient to identify the transferred entity. Whole-species electron counts are accounting totals, not measured partial charges or tracked electron trajectories. No equilibrium constant, favored direction, pH or reaction extent is predicted.

Supplied donor and acceptor roles: HF donates to water packet

Reset keeps your prediction, captures and practice history.

Transfer H⁺, not a neutral H atom

Supplied roles: donor (acid) HF(aq); acceptor (base) H₂O(l). Construct each conjugate by editing its H inventory and net charge separately.

Choose the four product changesRemove one H nucleus from the donorDecrease donor charge by 1Add one H nucleus to the acceptorIncrease acceptor charge by 1

Switching packet retains the selected types of changes. Reset restores the initial hydrogen-only proposal; writing, saved captures and practice remain.

Role	Parent atoms; charge	Candidate atoms; charge	Product identification
Donor → conjugate base	H: 1, F: 1; 0	F: 1; 0	Unvalidated composition/charge candidate
Acceptor → conjugate acid	H: 2, O: 1; 0	H: 3, O: 1; 0	Unvalidated composition/charge candidate

The equilibrium symbol indicates reversible representations, not equal concentrations or equal preference for the two sides. Unvalidated candidates are not claims that stable species with those compositions exist.

Electron count = sum of atomic numbers − net charge. Change along donor branch: -1; along acceptor branch: 1. These are counts for entire species, not oxidation numbers, partial charges or observed electron trajectories.

Quantity	Before	After
F atoms	1	1
H atoms	3	3
O atoms	1	1
Total net charge	0	0

Global atoms: balanced. Global charge: balanced. Specified single-proton transfer: not yet constructed. No-change and hydrogen-only proposals show why the first two checks alone are insufficient.

Source and scope

OpenStax Chemistry 2e §14.1 supports proton donor/acceptor and conjugate-pair conventions, including bicarbonate's two roles. This is a species-accounting model, not a bond-level mechanism. Equilibrium constants and concentrations are needed for extent and pH; neither is supplied here.

Global atoms and charge balance, but the proposal is not the specified H⁺ transfer.

Removing or adding a proton changes nuclear charge and net species charge together. A proper one-proton transfer leaves each corresponding species electron count unchanged. The diagram is species-level bookkeeping, not an elementary mechanism.

Observation to attach to a capture

Captures retain supplied donor/acceptor roles and proposed product changes. Replay checks symbolic conjugate construction, not measured speciation, pH or electron trajectories.

Understand

Try: a balanced proposal can transfer the wrong thing

The starting proposal removes one hydrogen from HF and adds one to water, but leaves both net charges unchanged. Total hydrogen and total charge still balance. Inspect electron counts: the donor candidate loses one electron and the acceptor candidate gains one. This is not the specified transfer of H⁺ with zero electrons. The candidates are accounting proposals, not identified stable products.

Predict and repair both products

HF has ten electrons: nine from fluorine plus one from hydrogen, minus zero net charge. Removing H⁺ leaves F⁻ with nine protons and ten electrons. Water has ten electrons; adding H⁺ gives H₃O⁺ with eleven protons and ten electrons. Select both charge changes to match those counts.

For a species with total nuclear charge Z and net charge q, electron count is Z − q. Here Z is the sum of atomic numbers, not an oxidation number. A donor losing H⁺ has both Z and q decrease by one, so their difference stays unchanged. This does not mean an electron was added to the donor.

Understand conjugate pairs

The donor and its product differ by one proton: they form a conjugate acid/base pair. The acceptor and its protonated product form the other pair. Inspect ammonium donation, then water donating to ammonia. Water can take either role depending on its partner and the represented direction. The two parents are not themselves a conjugate pair merely because one is labeled acid and the other base.

Apply: bicarbonate has two roles

Construct bicarbonate donating to water: HCO₃⁻ + H₂O ⇌ CO₃²⁻ + H₃O⁺. Then construct water donating to bicarbonate: H₂O + HCO₃⁻ ⇌ OH⁻ + H₂CO₃. In the first, bicarbonate becomes one unit more negative; in the second, it becomes neutral. Capture both equations and identify the conjugate pairs.

This ability to donate or accept a proton is called amphiprotic behavior. Showing both representations does not establish equal product amounts or which is favored. Equilibrium constants, concentration and other conditions are needed for such conclusions; the activity supplies none of them.

Transfer and continue

Try all four changes switched off: global budgets pass, but no transfer occurred. Try a one-sided H change and diagnose the atom mismatch. Complete the unfamiliar negatively charged acid practice, then connect this representation to weak-acid equilibrium for the separate question of extent. The redox activity tracks electron equivalents; acid/base proton transfer is a different bookkeeping task.

Source and limits

OpenStax Chemistry 2e §14.1 provides proton-transfer and conjugate-pair conventions and the bicarbonate examples. The interactive construction and failure cases are original symbolic exercises. Whole-species electron counts are not measured partial charges or tracked electron trajectories. Bond rearrangement, reaction mechanism, pH and equilibrium extent are not simulated; saved writing requires independent review.

Compare the strengths of both members of a conjugate pair

In one solvent at one temperature, stronger proton donation corresponds to a weaker conjugate base’s tendency to accept that proton back. This compares conjugate partners under matched conditions, not equal concentrations or identical pH. Water can accept from an acid or donate to a base; proton donation and electron transfer are distinct reaction classifications.

Original supplied comparison: In water at the same temperature, fictional acid HA is stipulated stronger than HB. Identify their conjugate bases and predict which is the stronger base. Does merely doubling the concentration of HB change this stated intrinsic strength ordering?

Check the paired comparison

The conjugate bases are A⁻ and B⁻; B⁻ is the stronger base under the matched conditions. Changing concentration can change pH and ionized fraction without changing the stated equilibrium strength ordering. A quantitative mixture still needs equilibrium constants and inventories; a ranking alone does not determine the extent.

Relative acid and conjugate-base strengths, checked 31 October 2026. Brønsted–Lowry proton transfer is the required framework here; Lewis acid–base theory is not an added AP requirement.

Apply

Public practice checks a specific claim. It does not establish independent mastery.

Explain why losing H⁺ makes a donor one charge unit more negative without adding an electron. Contrast whole-species electron totals with partial charge and oxidation state. Explain amphiprotic behavior without claiming a pH or favored equilibrium direction.

Your explanation and limitations

Continue

Completion requires a saved prediction, at least one capture and a reflection. Presence checks do not grade your reasoning.

Skipping retains experiments and awards no mastery.

Previous: Infer equivalence without mistaking an endpoint for proof Next: Construct electron-matched halves and recognize dual roles

Save a science backup or import one

Science work is stored locally in this browser, separately from mathematics and AI. It does not sync automatically. Use this science-only backup; this checkout's older all-subject export does not include science.

A legacy file is available only when the complete snapshot fits the 36 MB limit. For larger snapshots, prepare a complete file set below; never discard notebooks to make a smaller file.

Choose a science backup (maximum 36 MB)

Matching imported notebook drafts replace their current drafts. Omitted lessons and known first attempts remain. Export your current work first if you want to retain both drafts.

Complete file sets and course backups

A file set can hold more work than one science file. Keep its manifest and every part together. Each file is limited to 36 MB. This format needs this version of LearnAI or a compatible newer version; older versions can use only the legacy single-file backup above.

Export scope

The set includes every saved science course and global continuation at this moment. Later edits need a new export. A conflicting tab exports its own visible work, which may differ from saved work in another tab.

Choose the manifest and all parts together

0 file(s) selected. File order and filenames do not determine identity. Missing, changed or conflicting parts block the entire restore; no good part is applied by itself.

Science storage: loading. No account or remote computation is required.