Pick out the correct statement regarding \(\mathrm{H}_{2} \mathrm{SO}_{4}\). (1) Concentrated \(\mathrm{H}_{2} \mathrm{SO}_{4}\) cannot oxidize \(\mathrm{HBr}\) and \(\mathrm{HI}\) to form \(\mathrm{Br}_{2}\) and \(\mathrm{I} 2\) respectively. (2) Concentrated \(\mathrm{H}_{2} \mathrm{SO}_{4}\) reacts with \(\mathrm{NaNO}_{3}\) or \(\mathrm{Na}_{2} \mathrm{SO}_{3}\) (3) Glucose when treated with concentrated \(\mathrm{H}_{2} \mathrm{SO}_{4}\) forms carbon. (4) When treated with \(\mathrm{H}_{2} \mathrm{SO}_{4}, \mathrm{HCOOH}\) forms \(\mathrm{CO}\) and \(\mathrm{H}_{2} \mathrm{O}\). (a) \(1,3,4\) (b) \(2,3,4\) (c) 1,3 , (d) \(1,2,3,4\)

The ability of concentrated sulfuric acid (H2SO4) to act as an oxidizing agent is one of its most notable chemical properties. When sulfuric acid is in its concentrated form, it has a high affinity for water and can remove hydrogen atoms from other compounds. This is known as dehydration, which is an oxidizing process.

Reactions with Halides

For example, concentrated H2SO4 can oxidize halides, such as hydrobromic acid (HBr) and hydriodic acid (HI), leading to the liberation of diatomic halogen molecules like bromine (Br2) and iodine (I2). This process occurs because the sulfuric acid accepts electrons from the halide, effectively increasing the oxidation state of the halogen. However, it's vital to note that while sulfuric acid can oxidize HBr and HI, it cannot oxidize hydrochloric acid (HCl) due to the relatively high oxidation potential of HCl.

• Oxidizes HBr to Br2.
• Oxidizes HI to I2.
• Does not oxidize HCl efficiently.

Concentrated sulfuric acid has a range of chemical properties that make it a valuable chemical in various industrial applications. It is a strong acid, capable of causing severe burns and decomposing many organic materials.

Dehydration and Charring

One of the most characteristic chemical properties of sulfuric acid is its powerful dehydrating ability. When organic compounds like glucose are exposed to concentrated H2SO4, they get dehydrated, leading to the formation of solid carbon and water. This reaction appears as charring, or the turning of substances black as carbon gets separated out.

Reaction with Carbon Compounds

Concentrated H2SO4 can also dehydrate carbon-based acids such as formic acid (HCOOH), resulting in the formation of carbon monoxide (CO) and water. This property is particularly important in understanding the behavior of concentrated H2SO4 with various organic compounds.

Apart from being an oxidizing agent, concentrated sulfuric acid also showcases its reactivity through interactions with halides. This acid can react with inorganic salts that contain halide ions, such as sodium halides.

Formation of Hydrogen Halides and Other Products

For example, concentrated H2SO4 will react with sodium bromide (NaBr) or sodium iodide (NaI) to produce hydrogen halides (HBr or HI) and then proceed to oxidize them to diatomic halogens (Br2 or I2) as mentioned previously. The sulfuric acid is reduced in the process, often to sulfur dioxide (SO2).

Understanding the reactions between concentrated sulfuric acid and various halide-containing compounds is essential. It demonstrates not only the acid's oxidative strength but also its role in synthetic chemistry where it is used to synthesize various halogen derivatives.

• Reacts with NaBr to form HBr and Br2.
• Reacts with NaI to form HI and I2.
• Concentrated H2SO4 acts both as an oxidizing agent and a reactant.