Questions And Worked Solutions For Chemistry WCH14 May 2020
IAL Chemistry WCH14 May 2020 Questions - Complete Paper (pdf)
- Bromine oxidises methanoic acid to carbon dioxide.
- The rate of the reaction between two compounds, Y and Z, was investigated.
The results are shown.
- The inorganic anti-cancer drug cis-platin, Pt(NH3)2Cl2, is hydrolysed by water to make it active. The reaction is
- Propanone reacts with iodine in acidic solution.
- The equation shows the hydrolysis of a bromoalkane
- The equation for an exothermic reaction is shown.
- The equation for the equilibrium decomposition of hydrogen iodide into hydrogen
and iodine can be written in two ways.
- A buffer solution contains ethanoic acid, with a concentration of 0.10 mol dm−3, and
sodium ethanoate, with a concentration of 0.050 mol dm−3.
- The graphs show the changes in pH during a series of titrations.
Each titration involves two solutions, each of concentration 0.1moldm−3.
- Which diagram shows the first step of the mechanism for the nucleophilic addition of
hydrogen cyanide to propanone in the presence of potassium cyanide?
- When propanone reacts with iodine in the presence of sodium hydroxide, the
precipitate formed has the formula
- Which of the following could not be formed when methylamine is added to
- In which of these esters is the percentage by mass of carbon 54.5%?
- An organic compound that reacts with both lithium tetrahydridoaluminate(III)
(lithium aluminium hydride) and magnesium could be
- The following methods can be used to distinguish between pairs of organic compounds
with no further tests.
- This question concerns calcium chloride, CaCl2.
(a) Some energy changes related to calcium chloride are shown
- This question concerns six isomers each with the molecular formula C5H10O2.
(a) Isomers A, B, C and D are structural isomers that all react with aqueous sodium carbonate
to produce carbon dioxide.
Isomer A is a straight-chain compound.
Isomer B has only two peaks in its high resolution proton NMR spectrum, both of
which are singlets.
Isomer C contains a chiral centre but isomer D does not.
Give the structures of these four isomers.
- This question concerns acidic solutions.
(a) (i) A solution of hydrochloric acid has a pH of 1.125.
Calculate the concentration of hydrogen ions and of hydroxide ions, in mol dm−3,
in this solution
(ii) Calculate the volume of water which must be added to 25.0 cm3
of this solution to increase the pH from 1.125 to 1.500, giving your answer to an
appropriate number of significant figures.
(b) Phosphoric(V) acid, H3PO4 , is a weak acid, which dissolves in water, giving the
(i) Identify the acids and bases in the spaces below Equation 2, linking the
acid-base conjugate pairs.
(ii) Explain why very little dissociation of the H3PO4− ion occurs in solutions of
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