Science

2-Bromo-2-methylpropane in aqueous ethanol: rate-determining heterolysis to the planar tert-butyl cation, fast capture by water, deprotonation to the alcohol — with the first-order rate law, racemisation and the competing E1 path all named.

Hydroxide on (S)-2-bromobutane in a polar aprotic solvent: backside attack 180° from the C–Br bond, a single concerted transition state with no intermediate, and Walden inversion to (R)-butan-2-ol under a second-order rate law.

2-Bromo-2-methylbutane heated in ethanol: slow ionisation to the tertiary carbocation, then loss of a β-hydrogen to a weak base, giving the more substituted Zaitsev alkene as the major product alongside SN1 substitution.

The four-corner palladium cycle: oxidative addition of the aryl halide, base-driven exchange to the hydroxo complex, transmetalation from the activated boronate, and reductive elimination that releases the biaryl and regenerates Pd(0).

Zinc and copper half-cells at 1.00 M joined by a salt bridge: oxidation at the negative anode, reduction at the positive cathode, electrons through the wire, ions through the bridge, and E°cell = +1.10 V with the Gibbs energy it implies.

25.00 cm³ of 0.100 M ethanoic acid titrated with 0.100 M NaOH: apparatus, the pH trace, and the four landmarks that matter — the acidic start, the buffer plateau, pH = pKa at half-equivalence, and an equivalence point above pH 7.