Chemistry Multiple Choice Question (MCQ) MDCAT,ECAT,ETEA

Q.20  The equal masses of neon,ammonia,oxygen and sulphur dioxide gases are kept in a vessel at same temperature then these gases are suddenly allowed to comes out from the vessel.The gas having maximum K.E and diffused rapidly is
A) Neon
B) Ammonia
C) Oxygen
D) Sulphur dioxide

Correct Ans: B
Explanation: According to Graham's law of diffusion of gases,the lighter gas diffuse rapidly and according to Kinetic interpretation of temperature the average K.E of each molecule of any gas at same temperature is equal to each other but total K.E will be greater for that gas which have greater number of moles or molecules.
So,formula used
moles(n) = mass(m)/Molar mass(Mr)
Suppose the equal mass of each gas = 1 g
nNH3 = 1 / 17
nNe = 1 / 20.18
nO2 = 1 / 32
nSO2 = 1 / 64
So NH3 is lightest gas(least molar mass) among the above gases and it has greater number of moles or molecules.NH3 will move faster and having maximum K.E.

Physics Multiple Choice Questions (M.C.Qs) MDCAT Topic #2 Motion and Forces

Multiple Choice Questions (M.C.Qs) MDCAT Topic #2 Motion and Forces

Q.1  At which angle,the K.E at maximum height will be 25 % of its initial K.E

A) 30'

B) 45'

C) 60'

D) 90'

 Q.2  A body moves in semicircle of radius 'r'.The ratio of displacement to distance is

A) π/2 

B) 2/π

C) 3/π

D) 4π

 Q.3  A car is going on motorway from Lahore to Islamabad ,suddenly its accelerater and breaks fail then in which direction impulse will be with velocity

A) 90 degree

B) 180 degree 

C) 0 degree 

D) 45 degree 

Q.4  At maximum height of projectile,the angle between velocity and acceleration will be

A)  90

B) 180

C) 270 

D) 360

Q.5  When the slope of velocity time graph is zero,it means which quantity must be zero

A) Displacement

B) Velocity 

C) Acceleration 

D) Mass

Answers : 
Q.1  C
Q.2  B
Q.3  B
Q.4  A
Q.5  £
Explanations:
Q.1
Answer is 60 degree because at maximum height only horizontal component is there,when  we will put the 60 degree angle  in  K.E formula at maximum height we  will get 1/4 of initial K.E
Q.2
 Solution: 
Use formula
2r / πr
When the body moves in semicicle then we get answer by dividing 2r/πr.Hence B is correct option.
Q.3  
 In this case because breaks and acceleraters are totaly failed so only road friction is there due to which impulse and velocity will have 180 degree angle with  each other.
Q.4 

At highest point velocity is horizontal and acceleration is always vertical.Hence angle always be 90 degree at maximum height
Q.5  

Biology Multiple Choice Questions on MDCAT Topic#10 Genetic

Multiple Choice Questions on Human Genetic 
1. Down’s syndrome is characterised by
down syndrome karyotype
A) 19 trisomy
B) 21 trisomy
C) only one X chromosome
D) two X and one Y chromosome

2. Which of the following is known as Royal disease?
A) Sickle cell anaemia
B) Haemophilia
C) Alzheimer’s disease
D)  Colour blindness

3. Patau’s syndrome occurs due to
A) Trisomy of 13th chromosome
B) Trisomy of 18th chromosome
C) Trisomy of 21st chromosome
D) Trisomy of 22nd chromosome

4. The most important example of point mutation is found in a disease called?
A) Thalassemia
B) Night blindness
C) Sickle cell anaemia
D)  Down’s syndrome

5. The syndrome in which individual somatic cell contains three sex chromosome XXX is called
A) Down’s syndrome
B) Super female
C) Turner’s syndrome
D) Klinefelter’s syndrome

6. Identify a Mendelian disorder from the following
A) Down’s syndrome
B) Klinefelter’s syndrome
C) Turner’s syndrome
D) Phenylketonuria

7. A man has enlarged breasts, spare hair on body and sex complement as XXY. He suffers from 
A) Down’s syndrome
B) Klinefelter’s syndrome
C) Turner’s syndrome
D) Edward’s syndrome

8. In a family, father is having a disease and mother is normal. The disease is inherited to only daughters and not to the sons. What type of disease is this?
A) Sex linked dominant
B) Sex linked recessive
C) Autosomal dominant
D) Autosomal recessive

9. In man, which of the following genotypes and phenotypes may be the correct result of aneuploidy in sex chromosomes?
A) 22 pairs + Y females
B) 22 pairs + XX females
C) 22 pairs + XXY males
D) 22 pairs + XXXY females

10. A woman with one gene for haemophilia and one gene for color blindness on one of the X chromosomes marries a normal man. How will the progeny be?
A) Haemophilic and colour blind daughters
B) All sons and daughters are haemophilic and colour blind
C) 50% haemophilic and colour blind sons and 50% normal sons
D)  50% haemophilic colour blind sons and 50% colour blind daughters

Answers:

1. B) 21 trisomy
2. B) Haemophilia
3. A) Trisomy of 13th chromosome
4. C) Sickle cell anaemia
5. B) Super female
6. D) Phenylketonuria
7. B) Klinefelter’s syndrome
8. A) Sex linked dominant
9. C) 22 pairs + XXY males
10. C) 50% haemophilic and colour blind sons and 50% normal sons

Chemistry Concept of Mole Lecture #1

CONCEPT OF MOLE

When relative mass of any substance represent in grams (g) is called one mole of substance or molar mass.

• The mole is related to mass,volume and number of particles of the given substance.

Examples:

There are four different chemical substances can be represent in moles.

i) Atom

Relative mass of Na atom = 23 amu

When it represent in grams it becomes

23 amu ----> 23 grams = One Mole or simply Mole = Molar atomic mass or Molar mass = One gram mole

ii) Molecule

Relative mass of H2O molecule = 18 amu

When it represent in grams it becomes

18 amu ----> 18 grams = One Mole or simply Mole = Molar molecular mass or Molar mass = One gram mole

iii) Formula Unit

Relative formula mass of NaCl = 58.5 amu

When it represent in grams it becomes

58.5 amu ----> 58.5 grams = One Mole or simply Mole = Formula unit mass or Molar mass = One gram mole

iv) Ion

Relative mass of H+ ion = 1.008 amu

When it represent in grams it becomes

1.008 amu ----> 1.008 grams = One Mole or simply Mole = Molar ionic mass or Molar mass = One gram mole

We know according to Avogadro's 

One mole of any substance = NA = 6.02 × 10^23 particles (atoms or molecules or formula units or ions)

In case of ideal gases one mole of ideal gase at STP (standard temperature and pressure) =Molar volume (Vm) = 22.414 dm3 = 6.02 × 10^23 atoms or molecules

Interconversion of different Quantities into Mole

i. Mass into Moles and vice versa

Moles (n) = Mass (m) / Molar mass (M)

ii. Number of particles into Moles

Moles(n) = Number of particles(N)/NA

iii. Volume of ideal gas into Moles

Moles (n) = Vol.(V)/Molar Vol.(Vm)
Relationship between different formulae

• m / Mr = N / NA
• m / Mr = V / Vm
• N / NA  = V / Vm

Q.1  The 4.4 g CO2 occupies ___________ volume at STP
A)  22.414 dm3
B)  11.207 dm3
C)  2.2414 dm3
D)  4.4000 dm3

Correct Ans: C
Explanation:
Use formula:
m / Mr = V / Vm
Or
V = m / Mr × Vm
V = 4.4 g / 44 g × 22.414 dm3
V = 0.1 × 22.414 = 2.2414 dm3
Q.2 How many total number of atoms and electrons are present in 1.8 g of NH4- ions
A) 3.01 × 10^23 and 1.2 NA
B) 6.01 × 10^22 and 12 NA
C) 1.20 × 10^23 and 1.1 NA
D) 6.01 × 10^23 and 11

Correct Ans: A
Explanation:
Use formula for calculating total no.of atoms
N / NA = m / Mr × atomicity
Or
N = m / Mr × NA × 5
N = 1.8 g / 18 gmol-1 × 6.02 × 10^23 × 5
N = 0.1 × 6.02 × 10^23 × 5
N = 3.01 × 10^23 (Total atoms)
Use formula for calculating total no.of atoms
N / NA = m / Mr × No.of es- in one ion
Or
N = m / Mr × NA × 12
N = 1.8 g / 18 gmol-1 × 6.02 × 10^23 × 12
N = 0.1 × 6.02 × 10^23 × 12
N = 1.2 ×  6.02 × 10^23 or 1.2 NA (Total electrons)


Note: Continue ...
Remaining lecture uploaded latter

MCQ MDCAT Topic#4A,F.Sc-I Ch#4,EATA

Q.25   Which of the following is molecular solid having strongest hydrogen bonding ?
A) Ice
B) Glucose
C) Ethylene Glycol
D) Iodine

Correct Ans: B
Explanation: The glucose is polar molecular solid having strongest hydrogen bonding due to six  -OH groups are present in the each molecule.The molecules of glucose are held together by hydrogen bonding due to the polar -OH groups .The melting point of glucose is higher than ice.The ice is also polar molecular solid with hydrogen bonding but in ice H-bonding is weaker than glucose.The ethylene glycol is a liquid with hydrogen bonding. The H-bonding in ethylene glycol is weaker than glucose.The iodine is non-polar molecular solid with LDF.In I2 H-bonding is absent.

Trick to find Hybridization in a molecule

Trick to find Hybridization in a molecule

Methods # 1
Find the number of atoms attached to the central atom. If it’s 4n sp3, 5? Simple sp3d, 6? sp3d2. Lone pairs are also present in hybridised orbitals; so water for example, Oxygen has 2 hydrogen around it and 2 lone pairs, total 4 hence? sp3. Multiple bonds are due to electrons in unhybridised orbitals. In this way, you won’t need to calculate. But be careful as this strategy may not work for transition metals.

Methode # 2
If the simple textbook explaination is not short for you let me tell you the same.

Count all the sigma bond, or rather count the number of atoms it is bonded to.
Count the number of bonds, coordination bonds don't count. Now see how many electrons should be free. It should be a multiple of 2
Now you have the number of lone pairs, add the number fo lone pairs and sigma bonds and you have the hybridisation. Just in case you don't know here's it.
1- nothing
2- sp
3- sp2
4- sp3/dsp2/sp2d/spd2/d2sp (besides sp3 all involve sp3 and you won't find them before coordination chemistry. For them there is no short cut. You have to analyse everything carefully to find the hybridisation.
5- sp3d
6- sp3d2
7- sp3d3
8- sp3d4

Explanation of remaining MCQs

Q.3
All types of chemical bonds are also called true bonds like ionic bond,covalent and coordinate covalent bonds.
A) In KOH ionic bond is present between K+ and OH- .The one covalent bond is present between O and H in OH- ion.
B) In H2O only two covalent bonds are present.
C) In NH4OH,the ionic bond is present between NH4+ ion and OH- ion.In OH- also one covalent bond and in NH4+ ion there is three covalent bonds between N and H atoms but one is coordinate covalent bond between N and H atom.
D)In [Co(H2O)6] hexaaqua cobalt(0) ,dative bonds are present between ligand and Co but covalent bonds are present in H2O
Q.4
The dative bond is always formed between one complete filled orbital and one half filled orbital because complete es- pair should be transfer from filled orbital to empty orbital.
Q.5
S > P is incorrect 1st ionization energy order .because we know group VA show abnormal I.E trend and group VIA has greater 1st I.E than group VA.The P has stable partially filled p-subshell due to three unpaired es- (like nitrogen) as compared to S.All other three orders are correct.

MCQs MDCAT 4-A ,F.Sc-I CH#6....Answer Key with Explanation

• Q.1 The nu2
• ber of sigma bonds ratio to pi-bonds in Toluene is

           A) 15 : 3
           B) 15 : 0
           C) 15 : 1
           D) 14 : 0

• Q.2 Which of the following is iso-structural with Carbonate ion

           A) PH3
           B) lF3
           C) SO3
           D) NH3

• Q.3 All types of chemical bonds are present in

            A) KOH
            B) H2O
            C) NH4OH
            D) [Co(H2O)6]

• Q.4   The dative bond is formed according to Valence bond theory between 

           A) Half-filled orbitals
           B) Empty orbitals
           C) Empty and full-filled orbitals
           D) Full-filled orbitals

• Q.5  The incorrect 1st ionization energy order is

           A) S > P
           B) Be > B
           C) He > F
           D) N > O  




          Answers :
          Q.1 = B             Q.2 = C             Q.3 = C                      Q.4 = C              Q.5 = A
          Explanation:
          Q.1  In toluene or methylbenzene there are six bonds present between C-C in the ring,one C-C bond between ring carbon and methly carbon,five C-H bonds with ring and three C-H sigma bonds in methyl group but there are delocalized pi-electronic cloud is present in the ring so no true pi-bonds are present in the ring according to modern orbital treatment structure of benzene. So 15 sigma binds and 0 pi-bonds.
        Q.2  The structure of carbonate ion resemble with SO3.Both follow AB3 pattern according to VSEPR theory.Following are structures of all compounds in options.

Q.3

welcome to visitors

MCQ Pic

MDCAT MCQs

Pictures attached:
1.

MCQs MDCAT Pics attached

Chemistry Ch#14 2nd year MDCAT Topic#8C

The challenging MCQ by Online entry test academy(OETA) from ch#14 Macromolecules

Q. A polypeptide chain containg 9999 amino acids is preffered to be called:
A.Polypeptide
B.Protein
C.Amino acids
D.Tertiary Protein

Correct Ans: B (Protein)
Explanation: A polypeptide chain which cintains 9999 amino acids must have molar mass greater than 10,000 g/mol so we know if polypeptide chain has molar mass greater than 10,000 g/mol than it is preferable to be called protein

MCQ MDCAT Topic# 1A

*Q.85 The one molecule of Hb(Haemoglobin) nearly consist of 10,000 different atoms.How many times one Hb molecule heavier than H2?*
A) 68,000
B) 34,000
C) 17,000
D) 4000

Correct Ans: B
Explanation : We know
 1 Hb = 68,000 times then 1 H atom
But 1Hb = 34,000 times than 1 H2 molecule
Note: H2 is given in the statement not H atom

MCQ Ch#14 (MDCAT Topic # 8C)

The challenging mcq by OETA

Q.22A polypeptide chain containg 9999 amino acids is preffered to be called:
A.Polypeptide
B.Protein
C.Amino acids
D.Tertiary Protein

MCQ Ch#1 Basic Concepts (MDCAT Topic# 1A)

*Q.85 The one molecule of Hb(Haemoglobin) nearly consist of 10,000 different atoms.How many times one Hb molecule heavier than H2?*
A) 68,000
B) 34,000
C) 17,000
D) 4000

MCQ-2 7A

The challenging MCQ by Online Entry test Academy(OETA)2018
(Note:Correct ans with explanation is given on OETA Group so join OETA group and get correct answer with explanation)

*Q.69 By increasing temperature of water from 25'C to 100'C then *
A) The pH of water decreases
B) The pOH of water increases
C) The pKw of water remains constant
D) The pH of water remains constant

Correct Ans : A (The pH of water decreases]
Explanation : By increasing temperature the decomposition of water also increases the Kw of water increases approximately 75 times so its mean both [H+] ions and [OH-] ions increases
Kw = [H+] [OH-] or pKw = pH + pOH
Hence we know:
pH = - log [H+]
if [H+] increases then pH decreases however pOH is also decreases because [OH-] ions are also increases.Overall sum of H+ ions and OH- ions increases so Kw increases or pKw decreases.H+ and OH- ions equally increases so water is always neutral at any state.
Remember: by changing temp. Kw,pKw,pH,pOH.H+ and OH- all changes except neutrality of water remains constant.

MCQ

The challenging MCQ by Online Entry test Academy(OETA)2018
(Note:Correct ans with explanation is given on "Online entry test academy" Group so join "online entry test academy" group and get correct answer with explanation)

*Q.55 2SO2 + O2 <=====> 2SO3 Delta H = -ve
On increasing temperature of the above reaction then *
A) The concentration of SO2 decreases
B) The concentration of SO3 increases
C) The value of Kc increases
D) The rate of reaction increases

Correct Ans : D [The rate of reaction increases]
Explanation : The above reaction is reversiable exothermic reaction.According to kinetic theory and Arrhenius theory by increasing temperature the rate of reaction (exo or endo) always increases however in case of exothermic reaction the rate of backward direction increases as many times as compared to farward (forward also increases but with less speed). High temperature favours the overall backward direction so reactants increases and products decreases.
We know
Kc = [P]/ [R]
So Kc decreases on increasing temperature.