Edexcel Jun 2010 Paper 5 Q23

Answers available below

PMT (2) 23 More than half of the elements in the Periodic Table are transition elements. Vanadium, element 23, is a typical transition element. (a) (i) Give TWO properties shown by vanadium compounds that are characteristic of transition metal chemistry, other than variable oxidation state.(ii) Vanadium(III) ions in aqueous solution exist as [V(H2O)6]3+. Draw this ion so as to clearly show its shape. Name the type of bond between the ligand and the vanadium ion and state the feature of the ligand that enables this bond to be formed. (3)*N36507A01728* 17 Turn over<br /> PMT (b) Vanadium ions exist in oxidation states from (V) to (II). (i) Use your data booklet (page 15) to find the standard electrode (reduction) potential for the reduction of vanadium(IV), VO2+, to vanadium(III), V3+. (1)*(ii) Explain the term disproportionation. (2)(iii) Use your answer to (b)(i), and the data below, to calculate Ecell for the formation of vanadium(V) and vanadium(III) from vanadium(IV) in acidic solution. State if the reaction is feasible under standard conditions and justify your answer. VO2 +(aq) + 2H+(aq) + e (cid:85) VO2+(aq) + H2O(l) E= + 1.00 V (2)(Total for Question 23 = 10 marks) TOTAL FOR SECTION B = 47 MARKS 18 *N36507A01828*<br />

Show answer