Question
Chemistry Question on Expressing Concentration of Solutions
The amount of H2S. required to precipitate 1.69 g BaS from BaCl2 solution is:
A
3.4 g
B
0.034 g
C
0.34 g
D
0.17g
Answer
0.34 g
Explanation
Solution
Key Idea: First write balanced chemical reaction and then find the answer. BaCl2+H2SBaS+2HCl Molecular mass of H2S=1×2+32=34 Molecular mass of BaS=137+32=169 Given mass of BaS=1.69g According to reaction. ∵ 169g of BaS is obtained by =34g of H2S ∴ 1.69 g of BaS is obtained by =16934×1.69 =0.34gofH2S