- $\ce{HgCl2}$ and $\ce{I2}$ both when dissolved in water containing $\ce{I-}$ ions the pair of species formed is
A. $\ce{HgI2, I3-}$
B. $\ce{HgI2, I-}$
C. $\ce{HgI4^2-, I3-}$
D. $\ce{Hg2I2, I-}$
Answer: option (c)
In this question, I was able to predict the formation of $\ce{I3-}$. So, I could eliminate option (b) and (d). But, between option (a) and (d), I could not distinguish. Is there any specific way to guess answers for these type of questions in exam?