Introduction

Q.

Identify the ${\mathrm{Mg}}^{2+}$ ion from Fig. where $\mathrm{n}$ and $\mathrm{p}$ represent the number of neutrons and protons respectively.

1. 

2. 

3. 

4. 

Q. The one which is composed of all the three kinds of bond
(ionic, covalent and coordinate bond )

1. Ammonium chloride
2. Sodium chloride
3. Ammonia
4. Carbon tetrachioride

Q.

Why acids or bases do not react with plastic and similar items?

Q.

The number of neutrons present in ${}_{92}^{238}\text{U}$ are:

1. 148

2. 146

3. 144

4. 92

Q. 2NaCl + H2SO4-------Na2SO4 + 2HCl OR NaCl + H2SO4 ------NaHSO4 + HCl Which one is correct

Q. What are alkali and non - alkali , metals and non - metals?

Q. Which one of the following is relative periodic property? a) Electronegativity b) Electron affinity c) Atomic radii d) Ionic radii

Q.

An element ‘X’ has an atomic mass number = 27. If the number of electrons = 13. Then the number of neutrons will be _____.

1. 13

2. 16

3. 14

4. 15

Q. How to balance charges in chemical equations?

Q.

Isobars differ in____.

1. Number of nucleons

2. Atomic number

3. Atomic mass

4. Valence electrons

Q.

${}_{12}^6\text{C}{,}_{14}^6\text{C}{,}_{16}^6\text{C}$ differ in number of __________.

1. Protons

2. Electrons

3. Neutrons

4. Sum of protons and electrons

Q.

An element ‘X’ has atomic mass number = 27. If the number of electrons = 13. The number of neutrons will be _____.

1. 14

2. 15

3. 16

4. 13

Q. Any chemical element (X) can be represented as${}_Z{X}^A$ where ‘Z’ is the atomic number and ‘A’ is the mass number. The Atomic number refers to the number of protons and the mass number refers to the sum of protons and neutrons in an atom. For an element, calcium which has 20 protons and 20 neutrons, identify the correct representation.

1. ${}_{20}C{a}^{40}$
2. ${}_{40}C{a}^{20}$
3. ${}_{20}C{a}^{20}$
4. ${}_{20}C{a}^{60}$

Q.

Give one example of isobars.

Q.

Some carbon atoms have mass number 12 and some have mass number 14. These atoms of same element of different mass numbers are called __.

Q.

An element ‘X’ has mass number = 27. If the no. of electrons is given as 13, the no. of neutrons will be ___ .

(Assume that atom is neutral)

Q. 27. In case of hydride of group 15 bond angle decreases down the group but it is said that the bond angle is less than expected dua lone pair bond pair repulsion and down the group this repulsion decrease so bond angle should increase? ?

Q. Question 19.1

Write the balanced chemical equation for the following reaction and identify the type of reaction.

Nitrogen gas is treated with hydrogen gas in the presence of a catalyst at 773K to form ammonia gas.

Q. Give balanced equation when:
(b) ethene reacts with chlorine

Q. Consider the following chemical reactions.

निम्नलिखित रासायनिक अभिक्रियाओं पर विचार कीजिए।

NaCl + H₂O + CO₂ + NH₃ → NH₄Cl + A

A + HCl → NaCl + B + C↑

$2\text{A}\stackrel{\text{Heat}}{\to }\text{D + B + C}\uparrow$


Now, identify A, B, C and D and choose the correct option.

अब A, B, C तथा D को पहचानिये तथा सही विकल्प का चयन कीजिए।

1. C = CO₂
   
   B = H₂O
   
   A = NaHCO₃
   
   D = NaOH
2. A = Na₂CO₃
   
   D = NaHCO₃
   
   C = CO₂
   
   B = H₂O
3. C = CO₂
   
   B = H₂O
   
   A = NaHCO₃
   
   D = Na₂CO₃
4. C = H₂O
   
   D = NaHCO₃
   
   A = NaOH
   
   B = CO

Q. Any chemical element (X) can be represented as ${}_Z{X}^A$ where ‘Z’ is an atomic number and ‘A’ is the mass number. For an element, calcium which has 20 protons and 20 neutrons, identify the correct representation.

1. ${}_{20}C{a}^{40}$
2. ${}_{20}C{a}^{60}$
3. ${}_{40}C{a}^{20}$
4. ${}_{20}C{a}^{20}$

Q.

An element ‘X’ has mass number 27. If the number of electrons is given as 13, the number of neutrons is:

1. 15

2. 16

3. 13

4. 14

Q.

What will be the mass of carbon dioxide made from ${}_6^{14}\text{C}$?

1. ⁴⁴

2. 46

3. 48

4. 50

Q. An element with mass no. 81 contains 31.7% more neutron as compared to protons so actomic no is:

1. 55
2. 13
3. 35
4. 42

Q. what is alchemy ?is it actually possible to convert base metals in noble metals? what are the methods?are alchemist still there

Q. Ethanol can be converted into ethene which can be changed into ethane. Choose the correct word or phrase from the brackets to complete the following sentences.

(c) The conversion of ethene into ethane is an example of .
(hydration, hydrogenation).

Q. Balance the equation C6H6 +O2 ----> CO2+ H2O. Explain it with proper steps.

Q. Convert ethanol into ethene using
(b) hot conc. $H_{2}S{O}_4$
Give only balanced equations.

Q.

The number of elements which occur in nature is _______.

Q. Reaction conditions such as temperature and pressure affect the rate at which it takes place.

1. True
2. False