HF and HCN are both weak acids. Ka = 3.5 x 10-4 for HF Ka = 4.9 x 10-10 for HCN What is [CN-] in a mixture of 0.50 M HF and 0.30 M HCN. A. 1.2 × 10-5 M B. 7.4 × 10-6 M C. 2.4 × 10-10 M D. 1.1 × 10-8 M E. 3.7×10-6M

The scheme below is from a series of reactions that are part of a synthesis of vitamin a. answer the following questions with reference to this scheme. (i) what is "reagent a"? (ii) draw a step-by-step mechanism which explains the formation of compound c from compound b (iii) which reagents would you use to form compound e from compounds c and d (reagents b and c)? for each reagent suggested above in (ii) explain the role of the reagent in the reaction to (iv) form compound e. you may wish to do this by drawing a mechanism. 1. addition of reagent a но reagent a 2. н, о" thо oh нон-с compound a. compound b. compound c .ch-оh 1. reagent b "сно 2. reagent c сh oh compound e. compound d.

Which formula equation represents the burning of sulfur to produce sulfur dioxide? s(s) + o2(g) 4502(9) 2h2s(s) + 302(g) —> 2h20(0) + 2502(9) 4fes2+1102 —> 2fe2o3 + 8502 2802(g) + o2(9) v205 , 2503(9)

What is the empirical formula of a compound that is 50.7% antimony and 49.3% selenium ?