Copper is deposited at the cathode and is dissolved at the anode. Consequently the concentration of copper ions in solution remains constant. This can be used as a method of purification of copper as only pure copper is deposited at the cathode. Bubbles of gas (oxygen) are formed at the anode. Cathode reaction: Cu2+ + (aq) + 2e– ® Cu(s); and Anode reaction: 2H2O(l ) ® O2(g) + 4H+(aq) + 4e

Correct Option: A

Copper is deposited at the cathode and is dissolved at the anode. Consequently the concentration of copper ions in solution remains constant. This can be used as a method of purification of copper as only pure copper is deposited at the cathode. Bubbles of gas (oxygen) are formed at the anode. Cathode reaction: Cu2+ + (aq) + 2e– ® Cu(s); and Anode reaction: 2H2O(l ) ® O2(g) + 4H+(aq) + 4e

Potassium permanganate is an inorganic chemical compound with the formula KMnO4. As an oxidant, potassium permanganate can act as an antiseptic. For example, dilute solutions are used to treat canker sores (ulcers), disinfectant for the hands and treatment for mild pompholyx, dermatitis, and fungal infections of the hands or feet. It is used extensively in the water treatment industry.

Correct Option: D

Potassium permanganate is an inorganic chemical compound with the formula KMnO4. As an oxidant, potassium permanganate can act as an antiseptic. For example, dilute solutions are used to treat canker sores (ulcers), disinfectant for the hands and treatment for mild pompholyx, dermatitis, and fungal infections of the hands or feet. It is used extensively in the water treatment industry.

Butanes are highly flammable, colourless, easily liquefied gases. When blended with propane and other hydrocarbons, it is referred to commercially as LPG, for liquified petroleum gas. It is used as a petrol component.

Correct Option: B

Butanes are highly flammable, colourless, easily liquefied gases. When blended with propane and other hydrocarbons, it is referred to commercially as LPG, for liquified petroleum gas. It is used as a petrol component.

Fluorine is one of the most reactive elements in existence, attacking otherwise inert materials such as glass, and forming compounds with the heavier noble gases. It is a corrosive and highly toxic gas. The reactivity of fluorine is such that if used or stored in laboratory glassware, it can react with glass in the presence of small amounts of water to form silicon tetrafluoride (SiF4).

Correct Option: A

Fluorine is one of the most reactive elements in existence, attacking otherwise inert materials such as glass, and forming compounds with the heavier noble gases. It is a corrosive and highly toxic gas. The reactivity of fluorine is such that if used or stored in laboratory glassware, it can react with glass in the presence of small amounts of water to form silicon tetrafluoride (SiF4).

Electrons occupy shells around the outside of an atom. There can be up to two electrons in the first shell, up to eight in the second and up to eight in the third. A calcium atom (Ca) has electron structure 2,8,8,2.

Correct Option: C

Electrons occupy shells around the outside of an atom. There can be up to two electrons in the first shell, up to eight in the second and up to eight in the third. A calcium atom (Ca) has electron structure 2,8,8,2.