WJEC Chemistry for AS Level: Revision Workbook

SECTION B 6. Ammonia, NH 3 , phosphine, PH 3 and arsine, AsH 3 , are all gaseous compounds of group 5 elements. (a) State and explain which of these compounds will have the highest solubility. [2] ......................................................................................................................................................................................................................................................................................................................................... ......................................................................................................................................................................................................................................................................................................................................... ......................................................................................................................................................................................................................................................................................................................................... (b) State and explain which of these compounds will have the lowest boiling temperature. [3] ......................................................................................................................................................................................................................................................................................................................................... ......................................................................................................................................................................................................................................................................................................................................... ......................................................................................................................................................................................................................................................................................................................................... ......................................................................................................................................................................................................................................................................................................................................... (c) Ammonia can react with H + ions to form ammonium ions, NH 4 + . These ions contain both covalent and coordinate bonds. State what is meant by a coordinate bond and explain how it is different from a covalent bond. [2] ......................................................................................................................................................................................................................................................................................................................................... ......................................................................................................................................................................................................................................................................................................................................... ......................................................................................................................................................................................................................................................................................................................................... ......................................................................................................................................................................................................................................................................................................................................... (d) Phosphine can be produced by the decomposition of phosphorous acid, H 3 PO 3 : 4H 3 PO 3 r PH 3 + 3H 3 PO 4 M r = 82.03 M r = 34.03 M r = 98.07 Decomposition of 41.3 g of phosphorous acid produced 84.2% yield of phosphine. Calculate the mass of phosphine produced. [2] Mass of phosphine = ................................................................................ g 154 | WJEC Chemistry for AS Level: Revision Workbook | Practice papers