A. KAl( \(\left.SO _{4}\right) \cdot 12 H _{2} O\) B. \(Cu \left( NH _{3}\)_{4} Cl _{2}\) C. \(K _{2} S _{2} O _{1} .5 H _{2} O\) D. \(Mg ( OH ) Cl\)
Correct Answer: B
Explanation
Complex salts are those in which the positive and/or negative ions are complex or posses a coordination sphere e.g. \(K _{4} Fe ( CN )_{6}, \quad Cu \left( NH _{3}\right)_{2} Cl _{2}, \quad\left[ Cu \left( NH _{3}\right)_{6}\right]\left[ CuCl _{4}\right]\), \(\left[ Ag \left( NH _{3}\right)_{2}\right]_{3}\left[ Cr ( CN )_{6}\right] KAl \left( SO _{4}\right)\). \(12 H _{2} O\) is a double salt, \(K _{2} S _{2} O _{3} .5 H _{2} O\) is a normal salt, and \(Mg ( OH ) Cl\) a basic salt.