Zadania z chemii IB HL

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

Which statement is correct about an $\mathrm{S_N1}$ mechanism? A. The rate of reaction depends on the concentrations of both the halogenoalkane and the nucleophile. B. The rate-determining step forms a carbocation intermediate from a single molecule. C. The…

Which compound is the major product when 2-methylpropene, $\ce{(CH3)2C=CH2}$, reacts with hydrogen chloride, $\ce{HCl}$? A. $\ce{(CH3)3CCl}$ B. $\ce{(CH3)2CHCH2Cl}$ C. $\ce{CH3CHClCH2CH3}$ D. $\ce{(CH3)2CClCH2Cl}$

Two pigments extracted from a leaf are separated by thin-layer chromatography on a silica plate (a polar stationary phase) using a non-polar solvent as the mobile phase. Pigment X travels further up the plate than pigment Y. Which statement explains the…

Deduce the oxidation state of chlorine in each of the three chlorine-containing species in the equation. $\ce{Cl2}$: $\ce{HOCl}$: $\ce{Cl-}$:

The pool operators add sodium carbonate to the water to raise its pH. Explain why a larger proportion of the dissolved chlorine reacts with water after the sodium carbonate has been added.

A student writing a report on chlorine as a disinfectant collects, from several websites and reference books, values for how much chlorine dissolves in pure water at various temperatures. Source Temperature / °C Solubility of chlorine A 5 1.18 g per 100…

Most pools, including this lido, are dosed with sodium hypochlorite solution, $\ce{NaOCl(aq)}$, instead of chlorine gas. Suggest why pool operators avoid dosing the water with chlorine gas itself.