Question

General Acid-Base Concepts – Answer the following questions or provide explanations for the following using any and all of the acid-base concepts discussed in Chapter 6. (3 Pts each = 18 Pts)

a. The conductivity of BrF3 is increased by adding KF.

b. AlF3 is insoluble in HF but dissolves if NaF is added. However, if BF3 is added AlF3 precipitates.

c. Most of the metals used in antiquity were class (b) (soft in HSAB terminology) metals. (Hint: look up mp data and check to see which ones exist as oxides vs sulfides).

d. Rank the following acids in order of acid strength in aqueous solution: HMnO4, H3AsO4, H2SO3, H2SO4

e. Rank the following in order of increasing Brønsted Acid: SnH4, SbH3, TeH2 f. Rank the following in order of increasing Brønsted Base: NH3, PH3, SbH2

Answer 1

a) Bitz + KF ² Buty +60 Addition of KF leads to formation of ions as Bu fy and kt. As ions are conductive, its conductivity increases . Anhydrous. HF is a covalent compound and is strongly H-bonded. Therefore, it doesn't give F ions and hence Alfa cloesn't dissolve in hf. Naf is an ionic compound, it contains f-ions which combine with ē deficient Alf; to foum the soluble complex e molto inte 3 Naf& Alfz Naz(ALF6]. Bocon due to its small size and higher electro- negativity has greater tendency to form complexes than Aluminium. Hence, precipitation of Alfs takes place when BF3 is passed the ough NaB CALF Isol. NazEAlfo] + 3BF3 + 3NaCBF4]. d) H₂SO4 H₂SO3 H₂ AsOy, Hino Hana Strong - weak pro eve Hot (In aqueous solution) © 1) stepengest Bronsted acid : Satty, SbH3, TeHe. Bronsted and Lowry defined an acid as a specics which has the tendency to donate a hydrogen gon. Here we are given sn Hy, SbHz) Teta. As we move from left to right along the

period, the electronegativity of the elements increases from In to te Hence, Te H₂> SbH₂> Sntly haght i Te He is the strongest acid, in decreasing order of acidic strength - 1 ii) Bitta < Sblz < AS H₃ <PH₃ < NH3 NH₃ is the most basic compound Antiquity metals are gold, silver, copper, tin, ison, lead and mencery w . Gold, silver, mencury - native state Tin liron, lead - slides .... Copper present as both sulphites & oxides - Lead.