Zadania z chemii IB HL

In which species does an atom have the oxidation state +5? I. $\ce{IF5}$ II. $\ce{H3PO4}$ III. $\ce{N2O4}$ A. I and II only B. I and III only C. II and III only D. I, II and III

Sulfur has different oxidation states in hydrogen sulfide, $\ce{H2S}$, and in sulfurous acid, $\ce{H2SO3}$. Which pair of values is correct? A. $\ce{H2S}$: +2; $\ce{H2SO3}$: +4 B. $\ce{H2S}$: −2; $\ce{H2SO3}$: +6 C. $\ce{H2S}$: −2; $\ce{H2SO3}$: +4 D.…

In which compound does nitrogen have an oxidation state of +3? A. $\ce{NH3}$ B. $\ce{HNO2}$ C. $\ce{NO2}$ D. $\ce{HNO3}$

In the Claus process, used to recover sulfur from refinery gases, sulfur dioxide reacts with hydrogen sulfide, $\ce{H2S}$, to form sulfur. (i) State the oxidation state of sulfur in $\ce{SO2}$ and in the sulfur produced. (ii) Deduce the balanced equation for…

Methanoic acid, $\ce{HCOOH}$, is a weak acid, and solutions of it are often used as acidic buffers. A chemist prepared a $0.500\ \mathrm{mol\,dm^{-3}}$ solution of methanoic acid, in which two conjugate acid–base pairs are present. (i) For each pair, state the…

What are the oxidation states of the elements in $\ce{K2MnO4}$? A. K: +1, Mn: +6, O: −2 B. K: +1, Mn: +7, O: −2 C. K: +2, Mn: +4, O: −2 D. K: +1, Mn: +6, O: −1

Which row identifies the oxidizing agent and the reducing agent in the reaction below? $\ce{3Cu(s) + 2NO3^-(aq) + 8H+(aq) -> 3Cu^2+(aq) + 2NO(g) + 4H2O(l)}$ A. Oxidizing agent: $\ce{Cu}$, reducing agent: $\ce{NO3^-}$ B. Oxidizing agent: $\ce{NO3^-}$, reducing…

Which statements are correct for the complex ion $\ce{[CoCl4]^2-}$? I. The oxidation state of cobalt is +4. II. The chloride ions act as Lewis bases. III. The coordination number of cobalt is 4. A. I and II only B. I and III only C. II and III only D. I, II…

What is the oxidation state of chromium in the complex $\ce{[Cr(NH3)4Cl2]Cl}$? A. +1 B. +2 C. +3 D. +7