Chemistry Test - 3

Liebig's method is basically used for the estimation of Carbon and hydrogen in which we heat a known mass of organic compound in the presence of pure oxygen after that the carbon dioxide and water formed are collected and weighed and percentages of carbon and hydrogen are calculated from the masses of carbon dioxide and water.

Suppose if the compounds also containing nitrogen, as we know that during the combustion process organic nitrogen is oxidized in its oxides form i.e. NO,NO₂ which are also absorbed in potassium hydroxide solution along with carbon dioxide.

But other than this if we place a preheated CuO gauze near the exit of the combustion tube then we will notice that the oxides of nitrogen are reduced to nitrogen.

An antacid is a substance that neutralizes stomach acidity and is used to relieve heartburn, indigestion, or an upset stomach. Some antacids have been used in the treatment of constipation and diarrhea. Currently marketed antacids contain salts of aluminum, calcium, magnesium, or sodium.

Sodium carbonate is a chemical compound with the molecular formula Na₂CO₃. It's commonly referred to as washing soda and is used in cleaning products, glass production, as a food additive, and more.

A compound has an empirical formula \(\mathrm{CoCl}_{3} .5 \mathrm{NH}_{3}\). When an aqueous solution of this compound is mixed with excess of silver nitrate, 2 moles of \(\mathrm{AgCl}\) precipitates per mole of the compound. On reaction with excess of \(\mathrm{HCl}\), no \(\mathrm{NH}_{4}^{+}\); is detected. Hence the compound is \(\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{5} \mathrm{Cl}\right] \mathrm{Cl}_{2}\).

As the moles of \(\mathrm{AgCl}\) precipitated is 2 and \(\mathrm{no} \mathrm{NH}_{4}^{+}\) is detected on reaction with excess of \(\mathrm{HCl}\), so the compound would be \(\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{5} \mathrm{Cl}\right] \mathrm{Cl}_{2}\).

Higher aldehydes are soluble in Benzene. Therefore, statement (B) is correct.

Lower Aldehydes are pungent but higher Aldehydes are fragrant. Therefore, statement (A) is incorrect.

Acetone is more polar than n-Butane and weight is comparable, so acetone has higher boiling point. Therefore, statement (C) is incorrect.

Methanal is soluble in water. Therefore, statement (D) is incorrect.

Carbon monoxide binds to haemoglobin to form carboxyhaemoglobin, which is about 300 times more stable than the oxygen-haemoglobin complex.

In blood, when the concentration of carboxyhaemoglobin reaches about \(34 \%\), the oxygen-carrying capacity is reduced greatly leading to a lack of oxygen in the body.

In the presence of peroxide, hydrogen chloride and hydrogen iodide do not give anti-Markovnikov's addition to alkenes because one of the step is endothermic in both the cases.

HI and HCl do not do this for energetic reasons. The addition of Cl and I radicals to alkanes in an anti-Markovnikov fashion is an endothermic reaction and therefore counterproductive.

Without the presence of peroxide, all hydrogen halides will add according to the Markovnikov rule.

More the nuclear charge on ion, electrons are more strongly attracted, and thus size decreases. Therefore the correct order is: Na⁺ < Mg²⁺ > Al³⁺ < Si⁴⁺. Thus, the smallest size is aluminum ion.

The Sodium carbonate will not act as antacid.

• An antacid is a substance which neutralizes stomach acidity and is used to relieve heartburn, indigestion or an upset stomach.
• Antacids contain alkaline ions that chemically neutralize stomach gastric acid, reducing damage and relieving pain.

Examples of antacids are-

• Sodium hydrogencarbonate, Magnesium hydroxide, Aluminium carbonate, Aluminium hydroxide.  

Sodium carbonate known as washing soda is quite alkaline in nature and has a horrid soapy taste. It is not very palatable and could burn the throat. Therefore, it will not act as Antacid.

Ether is formed when alkyl halide is heated with sodium alkoxides. This method is called Williamson's Synthesis.

Ethers can be prepared in the laboratory by Williamson's synthesis.

In this method, when an alkyl halide is treated with sodium alkoxide, the nucleophilic substitution of the halogen atom by the alkoxide group takes place.

The general example is given below.

Williamson's synthesis is used to prepare symmetrical as well as unsymmetrical ethers.

As the reaction is a nucleophilic substitution reaction, the alkyl halide should be primary alkyl halide, using secondary and tertiary alkyl halide will yield alkenes due to elimination reaction and not ethers.

It is preferable to take secondary or tertiary alkoxide ion and primary alkyl halide.

The term "hydrogen economy" refers to the vision of using hydrogen as a low-carbon energy source – replacing, for example, gasoline as a transport fuel or natural gas as heating fuel.