UP PGT Chemistry Mock Test - 10 - UPTET MCQ

The correct answer is option B
Benzene - methanol shows a positive deviation from Raoult's law.
Benzene reduces H -bonding between methanol molecules and thus, evaporation increases or boiling point decreases, i.e., positive deviation from Raoult's law.Thus  in benzene - methanol mixture the intermolecular forces of attractions are weaker than those in pure liquids.

Electron gain enthalpy values of noble gases are positive because they have stable electronic configuration and thus have no tendency to take additionalelectron.

Tetracyanomethane, where σ bond =8, ratio = 1, π bond = 8.

 Carbon dioxide, O=C=O

σ = 2, π = 2 

Ratio = 1.

Also X, has CH₃— CH(OH)—, gives iodoform test and it is chiral.
 

[Pt(NH₃)₄]Cl₄ → 5 ions
[Pt(NH₃)₂Cl₄] → 0 ions
[Pt(NH₃)₄Cl₂]Cl₂ → 3 ions

The correct answer is B
Halogens have maximum negative electron gain enthalpy in the corresponding periods. This is due to the fact that the atoms of these elements have only one electron less than stable noble gas configurations. Electrons gain enthalpy of the elements of the group becomes less negative down the group. However, the negative electron gain enthalpy of fluorine.

The correct answer is option D
Zymase is an enzyme complex that catalyzes the fermentation of sugar into ethanol and carbon dioxide. It occurs naturally in yeasts. Zymase activity varies among yeast strains. Zymase is also the brand name of the drug pancrelipase.

The correct answer is option C
Demulsification is the breaking of a crude oil emulsion into oil and water phases. 
Demulsification is used to separate various mixtures like water in oil and oil in water etc.
It completely separates the constituent liquids and hence is the reverse of emulsification.

Sodium forms a basic oxide because it is a metal. Metals generally form basic oxides because they tend to donate electrons to oxygen atoms. In the case of sodium, when it reacts with oxygen, it forms sodium oxide, in which each sodium atom donates one electron to oxygen. This results in the formation of sodium ions (Na+) and oxide ions (O₂-), which can combine to form the ionic compound sodium oxide. Sodium oxide is basic because it can react with water to form a solution of sodium hydroxide, a strong base.

The correct answer is Option D
Tyndal effect is scattering of light when a ray of light is passed through a colloidal solution made forming a tyndall cone.

Energy of one photon
Energy supplied by one mole photon in KJ/mole = 3.11×6×10⁻¹⁹×6×10²³×10⁻³=297KJ/mole
% of energy converted to K.E.= 

Noble gases are inert they donot form any hydrides.

The atmosphere surrounding the Earth is made up of many gases, the most prevalent of which are nitrogen and oxygen. It also contains water vapor, dust and ozone. In the lowest layer of the atmosphere the troposphere the higher up you go, the lower the temperature.

NaX + HCl → NaCl + HX
[HX] at equivalent point = 0.05

Range of Indicator = 3 to 5

Be and Al show diagonal relationship and hence resembles each other closely.

Bohr Model of atom:

• An atom is made up of three particles: Electrons, neutrons and protons.
• The protons and neutrons are located in a small nucleus at the centre of the atom.
• The electrons revolve rapidly around the nucleus at the centre of the atom.
• There is a limit to the number of electrons that each energy level can hold.
• Each energy level is associated with a fixed amount of energy.
• There is no change in the energy of electrons as long as they keep revolving in the same energy level.

Bohr explained the stability through the concept of revolution of electrons in different energy levels.

The change in the energy of an electron occurs when it jumps from lower to higher energy levels. When it gains energy, it excites from lower to higher and vice versa.
Thus energy is not lost and the atom remains stable.

XeF₂ molecular geometry is linear. It acquires such shape as the lone pairs present around the central atom tend to take up equatorial positions. The bond angle is said to be 180°.

Requirement of macronutrient per acre of the land is 5 to 200 kg

Movement is always a mechanical property.

The non metallic character decreases down the group.And we know the oxides of non-metal r acidic in genral.Hence acidic character of oxides decreases down d group. Down the group the size of the element increases, electronegativity decreases ,metallic character increases and hence the acidic character decrease.

Since order of reaction with respect to RCl is one so if conc of RCl is halfed the rate of reaction will also become half.

(9) n = 3 can have suborbits

Total nine electrons.

Chemical Reaction take place between adsorbate and adsorbent in chemisorptions. Therefore it is specific in nature.

It has three chiral carbon, hence eight stereoisomers.

The correct observation about electrolysis is:

a) Electric current is used to drive a non-spontaneous reaction

Detailed Explanation:

1. Correct Option (a):

   • Electrolysis uses an external electric current to force a non-spontaneous redox reaction to occur.

   • In electrolysis, ΔG > 0 (non-spontaneous) and E°cell < 0, requiring energy input from the power source.

   • Example: Decomposition of water (2H₂O → 2H₂ + O₂), which doesn't occur spontaneously.

2. Why Other Options Are Incorrect:

   b) Ecell is positive and ΔG is negative:

   • This describes a galvanic/voltaic cell (spontaneous reaction that generates electricity), not electrolysis.

   • In electrolysis, Ecell is negative (non-spontaneous).

   c) Cations and anions are discharged at the cathode only

   • This is incorrect terminology.

     • Cations (positively charged ions) move to the cathode (where they gain electrons, reduction occurs).

     • Anions (negatively charged ions) move to the anode (where they lose electrons, oxidation occurs).

   • The statement reverses the actual process.

   d) Only overvoltage is responsible that a particular reaction takes place:

   • While overvoltage influences which reaction occurs (e.g., H₂ vs. Na⁺ discharge in aqueous NaCl), it is not the only factor.

   • Other factors include standard reduction potentials and concentration.

Key Concepts:

• Electrolysis requires energy input (electric current) for ΔG > 0 reactions.

• Cathode = Reduction (cations gain electrons).

• Anode = Oxidation (anions lose electrons).

• Overvoltage affects reaction preference but isn't the sole determinant.

Final Answer:

a) Electric current is used to drive a non-spontaneous reaction