Day 184: CBSE Class 10 Science

5 questions (8 parts). Try each one first, then open its answer.

Question 1
Metals and Non-metals. Asked once: 2026 (same type asked 3 times)
21 $Which one of the following metals does not react with cold water ?$
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Question 2 (case study, 4 parts)
Metals and Non-metals. Asked once: 2023 (same type asked 3 times)
The melting points and boiling points of some ionic compounds are given below :
Compound Melting Point (K) Boiling Point (K)
$\mathrm{NaCl}$ 1074 1686
$\mathrm{LiCl}$ 887 1600
$\mathrm{CaCl_2}$ 1045 1900
$\mathrm{CaO}$ 2850 3120
$\mathrm{MgCl_2}$ 981 1685
These compounds are termed ionic because they are formed by the transfer of electrons from a metal to a non-metal. The electron transfer in such compounds is controlled by the electronic configuration of the elements involved. Every element tends to attain a completely filled valence shell of its nearest noble gas or a stable octet.
37 (i) $Show the electron transfer in the formation of magnesium chloride.$
37 (ii) $List two properties of ionic compounds other than their high melting and boiling points.$
37 (iii) (A) $While forming an ionic compound say sodium chloride how does sodium atom attain its stable configuration ?$
37 (iii) (B) $Give reasons : (i) Why do ionic compounds in the solid state not conduct electricity ? (ii) What happens at the cathode when electricity is passed through an aqueous solution of sodium chloride ?$
Question 3
Metals and Non-metals. Asked once: 2023 (same type asked 3 times)
28 $With the help of suitable chemical equations, list the two main differences between roasting and calcination. How is metal reduced from the product obtained after roasting/calcination of the ore ? Write the chemical equation for the reaction involved.$
Question 4
Our Environment. Asked once: 2025 (same type asked 3 times)
16 $Green plants occupy the first trophic level in every food chain because they$
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Question 5
Our Environment. Asked once: 2024 (same type asked 3 times)
16 $Some wastes are given below : (i) Garden waste (ii) Ball point pen refills (iii) Empty medicine bottles made of glass (iv) Peels of fruits and vegetables (v) Old cotton shirt The non-biodegradable wastes among these are :$
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Compound	Melting Point (K)	Boiling Point (K)
$\mathrm{NaCl}$	1074	1686
$\mathrm{LiCl}$	887	1600
$\mathrm{CaCl_2}$	1045	1900
$\mathrm{CaO}$	2850	3120
$\mathrm{MgCl_2}$	981	1685

Question 1

Question 2 (case study, 4 parts)

Question 3

Question 4

Question 5