Chemistry

Chemical Bonding and Molecular Structure

1,420 Questions

This section tests your knowledge of chemical bonding, molecular structure, and hybridization. It covers ionic and covalent bonds, octet rule exceptions, and molecular geometry. These chemistry questions are common in various competitive entrance examinations.

Ionic and covalent bondsHybridisation of elementsOctet rule exceptionsMolecular geometryIntermolecular forces

Chemical Bonding and Molecular Structure Questions

Multiple choice bio-chemistry carbohydrate metabolism energy output living organisms and energy production respiration in cell

$\sim P$ in ATP represents

  1. Two bonds with high energy

  2. Two moles of phosphorus

  3. Three atoms of high energy phosphate

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
ATP is known as energy currency of the cell and it is a nucleotide formed by the combination of adenine as a nitrogenous base, ribose sugar, and triphosphate. It is found in free cells which breaks to form energy by breaking it's high energy phosphate bonds. The high energy phosphate bonds break to form ADP and AMP. It is a hydrolysis reaction which occurs at extreme pH. It dephosphorylates to provide energy for metabolic function.
ATP has three phosphate out of which one is directly attached to the ribose with phosphate ester bond and it is low energy bond. The bond between two phosphate groups is a phosphoanhydride bond which is considered as high energy bond. So ATP has only two high energy bond phosphoanhydride bond.
So, the correct answer is option A.
Multiple choice chemistry preparation of gases nitrogen gas component of air - nitrogen nitrogen

Among the following compounds, which on heating do not produce ${ N } _{ 2 }$?

  1. ${ \left( { NH } _{ 4 } \right) } _{ 2 }{ Cr } _{ 2 }{ O } _{ 7 }$
  2. ${ NH } _{ 4 }CI+Na{ NO } _{ 2 }$
  3. ${ NH } _{ 4 }CI+CaO$
  4. $Ba{ \left( { N } _{ 3 } \right) } _{ 2 }$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The reaction is given by,

$2 NH _4Cl + CaO → 2 NH _3 + CaCl _2 + H _2O$

Multiple choice chemistry preparation of gases nitrogen gas component of air - nitrogen nitrogen

Which of the following compound does not liberate nitrogen with $HNO _{2}$?

  1. Carbamide

  2. Primary amine

  3. Secondary amine

  4. Alkanamide
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Secondary amines do not read with $HNO _2$ to produce $H _2.$

$\Rightarrow R _2NH+H-O-N=0\rightarrow R _2N-N=0+H _2O$
Hence, the answer is secondary amines.

Multiple choice chemistry preparation of gases nitrogen gas component of air - nitrogen nitrogen

Which of the following compounds does not give nitrogen on heating?

  1. $NaN _3$
  2. $(NH _4) _2SO _4$
  3. $NH _4NO _2$
  4. $(NH _4) _2Cr _2O _7$.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

(A) $2NaN _3\xrightarrow {\Delta} 2Na+2N _2$
(B) $(NH _4) _2SO _4\xrightarrow {\Delta} 2NH _3+H _2SO _4$
(C) $NH _4NO _2\xrightarrow {\Delta} N _2+2H _2O$
(D) $(NH _4) _2Cr _2O _7\rightarrow N _2+Cr _2O _3+4H _2O$

Multiple choice chemistry preparation of gases nitrogen gas component of air - nitrogen nitrogen

Among the following compounds, which on heating do not produce ${N _2}$?

  1. (${NH _4}) _2 Cr _2 O _7$
  2. ${NH _4 Cl +Na NO _2}$
  3. ${NH _4 Cl+Ca O}$
  4. ${Ba(N _3) _2}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

(NH$ _4$)$ _2$Cr$ _2$O$ _7$ $\rightarrow$ N$ _2$ + Cr$ _2$O$ _3$ + H$ _2$O

NH$ _4$Cl + NaNO$ _2$ $\rightarrow$ N$ _2$ + H$ _2$O + NaCl

2 NH$ _4$Cl + CaO $\rightarrow$ 2 NH$ _3$ + CaCl$ _2$ + H$ _2$O

Ba(N$ _3$)$ _2$ $\xrightarrow{\text{heat}}$ Ba + 3N$ _2$

Thus, 2 NH$ _4$Cl + CaO will not produce N$ _2$.

Hence, the correct option is $\text{C}$
Multiple choice chemistry preparation of gases nitrogen gas component of air - nitrogen nitrogen

Which of the following compounds does not give $N _2$ when heated?

  1. $NH _4NO _2$
  2. $NH _4NO _3$
  3. $NaN _3$

  4. Both A and B
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$(1)NH _4NO _2\overset{\Delta }{\rightarrow}N _2+2H _2O$
$(2)NH _4NO _3\overset{\Delta }{\rightarrow}N _2O+2H _2O$
$(3)2NaN _3\overset{\Delta }{\rightarrow}3N _2+2Na$

Multiple choice evs experiments with water water and its types hard and soft water what floats - what sinks

Which of the following ions present as impurity cannot be removed by calgon process ?

  1. $Ca^{2+}$
  2. $Mg^{2+}$
  3. $Na^+$

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The Calgon process uses sodium hexametaphosphate (NaPO3)6 to sequester calcium and magnesium ions by forming soluble complexes. It does not remove sodium ions, as they are not responsible for water hardness and are often added by the process itself.

Multiple choice evs experiments with water water and its types hard and soft water what floats - what sinks

Which of the following pair of ions makes the water hard?

  1. $Na^+,SO _4^{+2}$
  2. $Ca^{2+},HCO _3^-$
  3. $Ca^{2+},NO _3$
  4. $NH _4^-,Cr$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Causes

1) High mineral (calcium and magnesium) content.
2) It can be found in groundwater as it passes through lime.
Types 
1) Permanent: It is caused due to the presence of sulphate and chloride salts.  Heating does not remove the permanent hardness of water so it is treated with chemicals.  Resins or water softeners are used to remove the permanent hardness.
2) Temporary: It is caused due to the presence of bicarbonate salts.  It can easily be removed by boiling.  Boiling decomposes the salts into insoluble carbonates.  Water can also be treated with calcium hydroxide to remove the hardness.Water Hardeners are Ca2+ and HCO3.   Nitrates and sulfates are used as water softener.  

Multiple choice evs experiments with water water and its types hard and soft water what floats - what sinks

Calgon removes hardness by forming complex compounds with the $Ca^{2+}$and $Mg^{2+}$ ions of hard water or by adsorption.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Calgon is $(Na _6P _6O _{18})$ i.e. sodium hexa-metaphosphate. The calgon when added to hard water forms a  soluble complex.


$Na _2[Na _4(PO _3) _6]+2CaSO _4\longrightarrow 2Na _2SO _4+Na _2[Ca _2(PO _3) _6]$ soluble

In the same way, $Mg^{2+}$ can also precipitate as $Na _2[Mg _2(PO _3) _6]$ and water becomes free from $Mg^{2+}$ and $Ca^{2+}$ ions.

Thus the answer is True.

Multiple choice evs experiments with water water and its types hard and soft water what floats - what sinks

In a permutit, the calcium and magnesium ions of hard water are exchanged by:

  1. $CO^{2-} _{3} $and $HCO _3{^-}$ ions of permutit
  2. $Na^{+}$ ions of permutit
  3. $Al^{3+}$ ions of permutit
  4. $Si^{4+}$ ions of permutiti
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Permutit is an artificial zeolite. It is sodium aluminium orthosilicate $Na _{2}Al _{2}Si _{2}O _{8}.xH _{2}O$.
$\underset {\text { permutit}}{Na _{2}Al _{2}Si _{2}O _{8}.xH _{2}O} + Ca^{2+}(or Mg^{2+}) \rightarrow  \underset {\text { exhausted permutit }}{Ca Al _{2}Si _{2}O _{8}.xH _{2}O} + 2Na^{+}$
Multiple choice chemistry metals physical properties of metals and non-metals some physical properties of metals general characteristics and uses of metals

Which of the following is non-malleable?

  1. Sulphur

  2. Chlorine

  3. Xenon

  4. None of the above
Reveal answer Fill a bubble to check yourself
A,B,C Correct answer
Explanation

Sulphur, chlorine and xenon, all are $p-$block elements.

Element I.e sulphur, chlorine, and xenon posses properties of non-metal like a poor conductor of heat and electricity,  electrons are not free to move, exist in the gaseous state.We know that non-metal are non-malleable. 


Multiple choice chemistry metals physical properties of metals and non-metals some physical properties of metals general characteristics and uses of metals

Which of the following is not malleable?

  1. Sulphur

  2. Selenium

  3. Phosphorus

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Non-metals are not malleable. They are brittle and hence they break easily. Such non-metals cannot be deformed by a hammer or rolling. Hence, non-metals cannot be deformed to form thin sheets.

Multiple choice commercial applications global environmental change causes of resource depletion causes of greenhouse effect ozone layer depletion

Which chemical is a 'ozone' depleting solvent?

  1. PAN

  2. CFCs

  3. Carbon tetrachloride

  4. Nitrogen
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Carbon tetrachloride (CCl4) is a well-known ozone-depleting substance historically used as a solvent in industrial and laboratory applications. While CFCs are also ozone-depleting, the question specifically asks for a solvent.