Chemical reaction and equation chapter deal with writing basic chemical reactions such as combination reaction, decomposition reaction, displacement reaction, double displacement reaction, oxidation, reduction etc and balancing the equations. It also guides the students through Chemical changes and changes in the elements. It thoroughly covers the law of conservation mass as well. Chemical reactions and equations has good weightage and according to our Experts, there are about 2-3 questions asked every year from this chapter. This chapter consists of the fundamentals of chemical reactions and equation, hence, clear concepts and preparation are crucial. NTSEGuru subject expert has complied important NTSE questions for the forthcoming examination.
1.In the reaction between ZnO and C as follows:
ZnO + C → Zn + CO
(a) Oxidizing agent
(b) Reducing agent
(d) None of the above
Ans: (b) Reducing agent
Sol: As it removes Oxygen from ZnO and C itself gets oxidized.
2. Rancidity is
(a) Oxidation of fats & oils
(b) Reduction of fats & oils
(c) Both (a) and (b)
(d) None of the above
Ans: (a) Oxidation of fats & oils
Sol: Oxidation of fats of oils by atmospheric oxygen to form products having a foul smell and bad taste is known as rancidity.
3. An Iron nail is dipped in blue coloured solution of Copper Sulphate. After some time Copper gets deposited on Iron and the blue coloured solution turns pale green indicating –
(a) Iron displaces Copper from its solution
(b) Copper displaces Iron from the nail
(c) Copper is more reactive than Iron
(d) None of these
Ans: (a) Iron displaces Copper from its solution
4. What happens when an electric current is passed through molten Sodium Chloride
(a) No reaction occurs.
(b) Sodium metal and Chlorine gas are formed.
(c) Vapours of Sodium Chloride are produced.
(d) Hydrogen and Chlorine gas are formed.
Ans: (b) Sodium metal and Chlorine gas are formed
Sol: Molten Sodium Chloride undergoes decomposition reaction on passing an electric current
5. In an endothermic reaction
(a) Energy of reactants > Energy of products
(b) Energy of reactants = Energy of products
(c) Energy of reactants < Energy of products
(d) Both (b) and (c)
Ans: (c) Energy of reactants < Energy of products
Sol: (c) As energy is absorbed by reactants to form products
These questions are important for the NTSE examination. Students are advised to go through these questions and in case of any doubts revise through the video lectures available at ntseguru.in