2006 Chemistry Paper 3 Marking Scheme — Kcse
Disclaimer: This post is a reconstruction based on standard marking guidelines for educational purposes. Always confirm with the official KNEC report. The Setup: Candidates were typically given a solution of hydrochloric acid (A) and a solution of sodium carbonate (B). They titrated to find the concentration of the acid.
| Procedure | Observation | Inference (Mark) | | :--- | :--- | :--- | | – Add NaOH dropwise then excess. | White precipitate formed, dissolved in excess NaOH. | Al³⁺ or Pb²⁺ or Zn²⁺ (1 mark for cation group). Confirm later. | | II. Confirm Pb²⁺ – Add KI solution. | Bright yellow precipitate. | Pb²⁺ confirmed (1 mark). | | III. Anion Test – Add dilute HCl to solid. | Effervescence (bubbles), gas turns limewater milky. | CO₃²⁻ (carbonate) (1 mark). | | IV. Sulfate test – Add BaCl₂ + HCl. | No white precipitate. | SO₄²⁻ absent (1 mark). | | V. Chloride test – Acidify with HNO₃, add AgNO₃. | White precipitate (curdy). | Cl⁻ present (1 mark). | kcse 2006 chemistry paper 3 marking scheme
KCSE 2006 Chemistry Paper 3: Marking Scheme & Practical Insights Disclaimer: This post is a reconstruction based on
If you need to share libs across workstations (eg. at a company) you can add a repository located on a shared network drive once it’s mapped in Windows. This is how we can lock library versions and not have any problems!
The only concern about sharing libraries through network shared folders is that if someone has to go then on a macchine in a non-connected environment, then the opening of library manager will take really long time (at last since o.s. returns timeout network availability error)…
Sometimes this is not the most efficient solution.
Very well written!