The ability of metals to be drawn into thin wire is known as:
Ductility
Malleability
Sonority
Conductivity
(1)
Ductility is the property which allows metals to be drawn into thin wires.
Which one of the following properties is not generally exhibited by ionic compounds?
Solubility in water
Electrical conductivity in solid state
High melting and boiling points
Electrical conductivity in molten state
(2)
Ionic compounds conduct electricity in aqueous solution or molten state. In solid state, they are non-conductors of electricity because of the absence of free ions.
Which of the following properties of aluminium makes it suitable for making cooking utensils?
(i) Good thermal conductivity
(ii) Good electrical conductivity
(iii) Ductility
(iv) High melting point
(i) and (ii)
(i) and (iii)
(ii) and (iii)
(i) and (iv)
(4)
Good thermal conductivity and high melting point of aluminium are the properties that make it suitable for making cooking utensils.
Which metal is displaced when zinc metal is put in the solution of copper sulphate?
Zinc
Copper
Sulphate
All of these
(2)
When zinc metal is put in the solution of copper sulphate, zinc displaces copper from its solution and forms zinc sulphate. This is because zinc is above copper in the reactivity series and is more reactive. The blue colour of the solution becomes colourless when zinc is added.
Silver articles become black on prolonged exposure to air. This is due to the formation of:
(3)
On prolonged exposure to air, silver metal reacts with hydrogen sulphide gas and forms a coating of silver sulphide . Due to this, silver loses its shine, turns black, and gets tarnished.
Which one of the following metals is found in liquid state at room temperature?
Na
Fe
Cr
Hg
(4)
Except mercury, all metals are solid at room temperature. Mercury is the only metal that exists in liquid state at room temperature.
Predict the metal when 2 mL each of concentrated HCl, and a mixture of concentrated HCl and concentrated in the ratio of 3:1 were taken in test tubes labelled as A, B, and C. A small piece of metal was put in each test tube. No change occurred in test tubes A and B but the metal got dissolved in test tube C.
Al
Au
Cu
Pt
(2)
Aqua regia is a mixture of three parts concentrated HCl and one part concentrated (3:1). Gold (Au) is a noble metal that does not dissolve in dilute acids but dissolves in aqua regia. Hence, the metal in test tube C is gold.
An alloy is:
an element
a compound
a homogeneous mixture
a heterogeneous mixture
(3)
Suspensions and colloids are heterogeneous mixtures, whereas an alloy is a homogeneous mixture of two or more metals. The properties of a metal can be improved by mixing it with another metal. metal such as melting point, electrical conductivity, resistant to corrosion and strong metals. Example of alloys are stainless steel (homogeneous mixture of Fe, Cr, Ni), brass (homogeneous mixture of Cu and Zn), bronze (homogeneous mixture of Cu and Sn) etc.
This element is very reactive to air and cannot be kept open in air. It reacts vigorously with water. Identify the element from the following.
Mg
Na
P
Ca
(2)
Element A is sodium as it is soft and can be cut with knife. It is kept in kerosene because it reacts vigorously when comes in contact with water or air.
Reaction between X and Y forms compound Z. X loses electron and Y gains electron. Which of the following properties is not shown by Z?
Has high melting point
Has low melting point
Conducts electricity in molten state
Occurs as solid
(2)
Reaction between compound X and Y forms compound Z. In the reaction, X loses electron and Y gains electron which means compound Z is a crystalline solid as ionic or electrovalent bond is formed between X and Y. As compound Z is a crystalline solid, it has high melting point and it conducts electricity in the molten state. Thus, the property not shown by Z is that it has low melting point.
