Chemistry Test-33

Ranitidine is a medicine use for reducing the amount of acid your stomach.

The molecular formula of propane is C₃H₈.

Alkanes are acyclic hydrocarbons in which carbon-carbon atoms have a single bond between them, i.e. they are saturated hydrocarbons. The general formula for alkanes is C_nH_2n+2, where, 'n' is the number of carbon atoms.

Propane is the third member of the alkane family with 3 carbon atom. If we put the number of carbon and hydrogen atoms present in propane in the above-mentioned formula, we will find that it holds true.

CH₄ is Methane, the first member of the alkane family.

C₄H₁₀ is Butane, the fourth in the line of alkanes.

C₂H₆ is Ethane, the second member of the alkane family.

The lower alkanes from C₁ to C₄ are gases, from C₅ to C₁₆ are liquids and beyond that are solids.

An element A belonging in Period \(3\) and Group II will have\(3\) shells and \(2\) valence electrons.

In the modern periodic table, horizontal columns are termed as groups and vertical rows are termed as periods. The period number indicates the number of the shells whereas the group number indicates the number of valence electrons.So, the element A has \(3\) shells and \(2\) valence electrons.

An exothermic reaction is one in which heat energy is liberated (given out) during the reaction. In the thermochemical equation for the exothermic reaction, the heat energy is on the product's side. The enthalpy of reactants is higher than the enthalpy of products.

Quick lime is calcium oxide. It reacts with water to form calcium hydroxide. The reaction of water with quicklime releases a large amount of energy. Hence, this is an exothermic reaction.

\(\mathrm{CaO}+\mathrm{H}_{2} \mathrm{O} \rightarrow \mathrm{Ca}(\mathrm{OH})_{2}+\) (Heat)

When concentrated sulphuric acid is diluted with water to obtain dilute sulphuric acid, a huge amount of energy is released. Thus, this reaction is an exothermic process.

Water absorbs heat and changes its state from liquid to through evaporation. Thus, evaporation of water is possible through absorption of heat energy. Thus, evaporation is an endothermic process and sublimation of camphor requires input of heat energy. So, it is also an endothermic process.

Neoprene is a polymer ofchloroprene.

Neoprene or polychloroprene is formed by the free radical polymerisation of chloroprene. It has superior resistance to vegetable and mineral oils. It is used for manufacturing conveyor belts, gaskets and hoses.

Acid rain is rain that is acidic, meaning it has a very low pH. When sulfur dioxide and nitrogen oxides are released into the air, they react with water and oxygen and produces sulfuric and nitric acids. These acids then mix with water and result in acid rain. Normal rainwater is slightly acidic with a pH range of 5-6. When the pH level of rainwater falls below this range, it becomes acid rain. It can have harmful effects on plants, aquatic animals and infrastructure.

It is not approved as a food preservative,is wrongstatement aboutsodium benzoate.

Sodium benzoate is a most commonly used food preservative.

• It is a manmade chemical compound which is known for its preserving property, and is commercially used as a famous preservative.
• It is commonly being used in many packed products to increase their shelf life such as cosmetics, jellies, pickles, medicines, sauces, and even the already prepared juices.
• It is a FDA approved product and is approved internationally as a food preservative and is known as E211 i.e., the assigned identity number.

Low boiling point metals like Mercury are purified with distillation.

The heat of copper makes the pole emit wood gas that reduces the cuprous oxide to copper. In poling, the molten impure metal is stirred with green poles of wood.

In electrolyte refining of metals, impure metal is made as Anode and a thin strip of pure metal is made as cathode.

Out of the substances Na, Hg, S, Pt, and graphite, only Pt and Graphite can be used as electrodes in electrolytic cells having aqueous solutions.

• Metals that are active and reactive towards oxidation and reduction reactions make up a good active electrode.
• Metals that are very unreactive in nature towards oxidation-reduction reaction make up as good inert electrodes.
• Na, S, and Hg can easily be oxidized and reduced and thus are active electrodes.
• Whereas, metals like Pt, Carbon, gold are unreactive and are inert electrode.
• Metals such as Pt are called noble metals because they are so unreactive that they don't even dissolve in strong acids.
• So, these metals can be used as electrodes to avoid unwanted reactions in the cell.

Hydrocarbons having single bonds are known as saturated hydrocarbon.

Saturated hydrocarbons are known as an alkane. These are also known as paraffin.Unsaturated hydrocarbons are having double or triple bonds i.e., alkenes and alkynes.A Saturated hydrocarbon is a hydrocarbon in which all the carbon-carbon bonds are single bonds.