51 . Which compound of oxygen is most likely to contain an O-O bond?
(A) CO 2
(B) NO 2
(C) SO 2
(D) H 2 O 2
(E) TiO 252 . Titanium tetrachloride, TiCl 4 , is a liquid at room temperature and has a very high vapor
pressure. Which statement best explains these observations?
Titanium tetrachloride is an ionic compound, with Ti4+ and Cl− ions arranged in a
lattice.(A)
Titanium tetrachloride is a molecular substance, with TiCl 4 molecules held together
by covalent bonds.(B)
The bonding in titanium tetrachloride is metallic, with a sea of electrons being
shared equally between all the atoms in a sample.(C)
Titanium tetrachloride is a network covalent substance, with an essentially infinite
lattice of covalently bonded Ti and Cl atoms.(D)
Titanium tetrachloride is simply a mixture of titanium atoms and chlorine atoms,
which are not bonded to each other in any particular way.(E)
53 . HCl (aq) + Zn (s) → ZnCl 2 (aq) + H 2 (g)
In the reaction above, which term best describes the role of HCl (aq)?(A) Brønsted acid
(B) Oxidizing agent
(C) Reducing agent
(D) Precipitate
(E) Cathode