Please refer to Metals and Non-Metals Class 10 Science Important Questions with solutions provided below. These questions and answers have been provided for Class 10 Science based on the latest syllabus and examination guidelines issued by CBSE, NCERT, and KVS. Students should learn these problem solutions as it will help them to gain more marks in examinations. We have provided Important Questions for Class 10 Science for all chapters in your book. These Board exam questions have been designed by expert teachers of Standard 10.
Class 10 Science Important Questions Metals and Non-Metals
Very short answer
Question: Give reason for the following observation : ionic compounds in general have high melting and boiling points.
Answer: Due to strong forces of attraction, the ions are bound to each other very firmly. As a result, the electrovalent or ionic solids have high melting and boiling points
Question: Name a reducing agent that may be used to obtain manganese from manganese dioxide.
Answer: Aluminium reduces manganese dioxide
(MnO2) to manganese (Mn). e reaction is highly exothermic.
3MnO2(s) + 4Al(s) Heat→ 3Mn(l) + 2Al2O3(s)
Question: Give reason for the following observation :
highly reactive metals cannot be obtained from their oxides by heating them with carbon.
Answer:The oxides of the most reactive metals such as sodium, potassium, magnesium, aluminium, etc. cannot be reduced by reducing agents such as carbon or aluminium. is is because these metals have more affinity for oxygen than carbon or aluminium hence, cannot be reduced by common reducing agents.
Question: What changes in the colour of iron nails and copper sulphate solution do you observe afer keeping the iron nails dipped in copper sulphate solution for about 30 minutes?
Answer: As iron (Fe) is more reactive than copper (Cu) so, iron displaces copper from its salt solution. Thus, blue coloured CuSO4 gets converted into pale green coloured FeSO4 afer keeping iron nails in CuSO4 solution.
CuSO4 + Fe→ FeSO4+ Cu
Blue Pale green
Question: (a) What are amphoteric oxides? Choose the amphoteric oxides from amongst the following oxides :
Na2O, ZnO, Al2O3, CO2, H2O
(b) Why is it that non-metals do not displace hydrogen from dilute acids?
Answer: (a) ose oxides which react with both acids
as well as bases to produce salts and water are
called amphoteric oxides.
Among the given oxides, Al2O3 and ZnO are amphoteric in nature.
(b) Non-metals do not displace hydrogen from dilute acids because non-metals do not provide electrons to change H+ ions into hydrogen gas.
Question: No chemical reaction takes place when granules of a solid, A, are mixed with the powder of another solid, B. However when the mixture is heated, a reaction takes place between its components. One of the products, C, is a metal and settles down in the molten state while the other product, D, floats over it. It was observed that the reaction is highly exothermic.
(i) Based on the given information make an assumption about A and B and write a chemical equation for the chemical reaction indicating the conditions of reaction, physical state of reactants and products and thermal status of reaction.
(ii) Mention any two types of reactions under which above chemical reaction can be classifed.
Answer: From the given information it is clear that A is Fe2O3 and B is Al.
(i) When A (Fe2O3) and B (Al) are heated then C (Fe) metal is formed which settles down in the molten state while D (Al2O3) floats over it. is reaction is exothermic in nature.
Fe2O3(s) + 2Al(s) Heat→ 2Fe(l) + Al2O3(s)
(ii) is reaction can be classifed under displacement reaction and redox reaction.
Question: Give reason for the following observation : Copper vessels get a green coat when left exposed to air in rainy season.
Answer: Copper vessels get a green coat when left
exposed to air in rainy season due to the formation
Question: What is meant by ‘rusting’? With labelled diagrams describe an activity to And out the conditions under which iron rusts.
Answer: Iron when exposed to moist air for a long time acquires a coating of a brown flaky substance
known as rust and this process is called rusting. Following activity can be performed to and out the
conditions under which iron rusts : Materials required : Iron nails, distilled water, turpentine oil, anhydrous calcium chloride. Procedure :
1. Take three test tubes and put one clean nail in each of them. Label them as A, B and C.
2. Pour some water in test tube A. In test tube B, pour some boiled distilled water along with some turpentine oil. In test tube C, add some anhydrous calcium chloride. 3. Leave these test tubes undisturbed for a few
Observations : Only in test tube A, iron nails get rusted since the nails in this test tube are exposed
to both air and water. Conclusion : Both air and water are required for rusting of iron.
Question: Write the names and symbols of two most reactive metals belonging to group I of the periodic table. Explain by drawing electronic structure how either one of the two metals reacts with a halogen. With which name is the bond formed between these elements known and what is the class of the compound so formed known? State any four physical properties of such compounds
Answer: Rubidium (Rb) and Caesium (Cs) are the two most reactive metals belonging to group-I of the periodic table.
Caesium (Cs) reacts with halogen say chlorine (Cl) to form caesium chloride as follows :
is bond formed by complete transfer ofelectrons between two elements is called ionicbond and the compound so formed is known asionic compound.Physical properties of ionic compounds are :
(i) Physical nature : Ionic compounds are solidsand are somewhat hard because of the strongforces of attraction between the positive andnegative ions.
(ii) Melting and boiling points : Ioniccompounds have high melting and boiling points.is is because a considerable amount of energy isrequired to break the strong inter-ionic forces ofattraction.
(iii) Solubility : ey are soluble in water andinsoluble in solvents such as kerosene, petrol, etc.
(iv) Conduction of electricity : A solution of anionic compound in water contains ions whichmove to the opposite electrodes when electricityis passed through the solution. ey conductelectricity in molten state as well as in aqueous
solution but not in solid state because movementof ions in the solid state is not possible due to theirrigid structures.
Question: Give reason why
(i) metals are good conductors, whereas non-metals are bad conductors of electricity.
(ii) metals replace hydrogen from acids whereas non-metals do not.
(iii) an iron knife dipped in a blue copper sulphate solution turns the blue solution light green.
(iv) sodium is kept under kerosene.
(v) carbon cannot reduce the oxides of sodium or aluminium.
Answer: (i) Metals are good conductors of electricity because they have free electrons or ions whilenon-metals do not contain free electrons or ions.
(ii) When a metal (which is more electropositive than hydrogen) is placed in an acid solution, it loses electrons. ese electrons are gained by H+ ions to produce hydrogen gas.
Non-metals do not have tendency to lose electrons.
(iii) As iron is more reactive than copper so, iron will displace copper from copper sulphate solution.
Fe+ CuSO4→ FeSO4+ Cu
Blue Pale green
Thus, blue coloured copper sulphate gets converted into light green iron sulphate.
(iv) Sodium catches are vigorously on reaction with oxygen at room temperature if kept in open. erefore, sodium is kept under kerosene.
(v) Carbon cannot reduce the oxides of sodium or aluminium because sodium and aluminium are placed at the top of the reactivity series and are highly reactive. ey have more anity for oxygen than carbon.
Question: (a) Distinguish between ‘roasting’ and ‘calcination’. Which of these two is used for sulphide ores and why?
(b) Write a chemical equation to illustrate the use of aluminium for joining cracked railway lines.
(c) Name the anode, the cathode and the electrolyte used in the electrolytic refning of impure copper3.5 Corrosion
Answer: (a) e process of heating an ore (generally a sulphide ore) strongly below its melting point inthe presence of an excess of air is called roasting.
Calcination is the process of heating an ore(generally a carbonate ore) strongly in the absenceof air or very limited supply of air. Roasting process is used for sulphide ores because sulphur gets oxidised to SO2 which can be easily
removed leaving behind the metal oxide.
(b) Aluminium displaces iron from iron oxide on heating.
Fe2O3(s) + 2Al(s) heat →Al2O3(s) + 2Fe(l) + Heat
this reaction produces lots of heat which results in the melting of railway track lines. Afer cooling, iron again forms a hard solid and hence, cracked railway lines can be joined.
(c) For electrolytic refning of impure copper, impure copper is used as anode, pure copper is
used as cathode and copper sulphate solution is used as the electrolyte.
Question: What is meant by refning of metals? Name the most widely used method of refning impure metals produced by various reduction processes. Describe with the help of a labelled diagram how this method may be used for refning of copper.
Answer: e process of purifying the impure (crude) metal is called ref ning of metals. the most widely used method of refning impure metals produced by various reduction processes is electrolytic refning. In electrolytic refning, a thick block of impure metal acts as anode. It is connected to the positive terminal of the battery. A thin sheet of pure metal
acts as cathode. It is connected to the negative terminal of the battery. An aqueous solution of a suitable salt of the metal is used as the electrolyte.
On passing current through the electrolyte, pure metal gets deposited on the cathode and the impure metal of the anode dissolves into the elctrolyte. e impurities either dissolve in the solution or settle down at the bottom of the anode as anode mud.