Which of the following undergoes nucleophilic substitution exclusively by SN¹ mechanism?

The order of stability of the following carbocations is

Which of the following bases is not present in RNA?

The hybridisation and the geometry of ICl₃ in liquid phase are ____ and _____, respectively.

Na⁺, Mg⁺⁺, Al³⁺ and Si⁴⁺ are isoelectronic. The order of their ionic size is

The number of geometrical isomers of [Cr(NH₃)(OH)₂Cl₃]^2– ion is

The compound in which metal exhibits more than one oxidation states, is

Most reactive alkene towards dil. HCl is

Number of dichloro derivatives that can be obtained from n-butane (excluding stereoisomerism) is

The reaction of CH₃ – CH = CH₂ with HOCl will yield

In the following question a statement of Assertion (A) followed by a statement of Reason (R) is given. Choose the correct option out of the choices given below each question.

Assertion (A): Smaller the size of an atom greater is the electronegativity.

Reason (R): Electronegativity refers to the tendency of atom so share electrons with other atom.

The resistance of 0.01 N solution of an electrolyte was found to be 210 ohm at 298 K, using a conductivity cell of cell constant 0.66 cm⁻¹. The equivalent conductance of the solution is

The rate of a first order reaction A → P is 4.5 × 10^-5 mol L^-1 s^-1, when the concentration of A is 0.5 mol L^-1. The rate constant for the reaction is

Maximum number of possible isomers of C₅H₁₂ is:

In the following question a statement of Assertion (A) followed by a statement of Reason (R) is given. Choose the correct option out of the choices given below each question.

Assertion (A): According to Mendeleev, periodic properties of elements is a function of their atomic number.

Reason (R): Atomic number is equal to the number of protons.

The prefix atto is used for the fraction

The following question has four choices out of which ONLY ONE is correct. Two vessels P and Q of equal volume (1 litre each) contain 6 g of O₂ and SO₂, respectively, at 300 K and 1 atm. Which of the following statements is correct?

Two isotopes of an element X are ¹⁴X and ¹⁵X. If the average atomic mass of X is 14.0067 u, what are the respective percentage abundances of ¹⁴X and ¹⁵X?

What is the number of carbon atoms present in 329 amu of tear gas (CCl₃NO₂)?

The following question has four choices, out of which ONLY ONE is correct.

An orbit differs from an orbital in that

The KE of an electron is 2.8 × 10^–23 J. Its de Broglie wavelength is nearly (Me = 9.1 × 10^–31 kg)

In the following question, two statements are given. One is assertion and the other is reason. Examine the statements carefully and mark the correct answer according to the instructions given below.

Assertion: The atoms of different elements, having same mass number but different atomic numbers, are known as isobars.

Reason: The sum of protons and neutrons in isobars is always different.

The elements with atomic numbers 9, 17, 35, 53 and 85 are all

Among the following elements (whose electronic configurations are given below), the one having the highest ionisation enthalpy is

The polarising power of the anions N^3-, O^2- and F^- follows the order:

Which of the following has the maximum ionisation potential?

Mendeleev proposed that some of the elements were still undiscovered and, therefore, left several gaps in the table. He left the gap under aluminium and a gap under silicon, and called these elements Eka-Aluminium and Eka-Silicon. These were later discovered and named

Which group of elements could be placed in Mendeleev's Periodic Table without disturbing the original order?

Arrange the following elements in the order of their increasing non-metallic character:

Li, C, Be, F, O

According to Dobereiner's triads, the atomic mass of the element is equal to the __________ of and elements in that triad.

It is now recognized that the ‘Modern Periodic Law’ is essentially the consequence of:

If three elements X, Y, and Z form a Dobereiner's triad and atomic weights of X and Z are 9 and 40 respectively, then the atomic weight of the element Y is approximate:

Sodium forms N^a+ ion, but it does not form Na²⁺ because of

The formation of oxide ion O^2- (g) requires first an exothermic and then an endothermic step as shown below:

O (g) + e^- → O^- (g), ΔHo = -142 kJ/mol

O^- + e^- → O^2- (g), Δ Ho = +844 kJ/mol

This is because

The correct order of increasing radii of the elements Na, Rb, K and Mg is:

Which of the following isoelectronic ions has the lowest ionisation energy?

Which of the following processes requires the highest energy?

The correct order of decreasing electronegativity values among the elements I - beryllium, II - oxygen, III - nitrogen, and IV - magnesium is

Which of the following electronic configurations corresponds to the element with the largest negative electron gain enthalpy?

Minerals associated with redox reactions are:

Oxidation number of carbon in CH₂Cl₂ is

The element that does not show positive oxidation state is:

Which of the following pairs of molecules has all the three types of bonds (electrovalent, covalent and coordinate)?

Which of the following substances would you expect to have the highest melting point?

The dipole moments of diatomic molecules AB and CD are 10.41 D and 10.27 D, respectively, while their bond distances are 2.82 Ao and 2.67 Ao, respectively. What does this indicate? [Electronic charge (q) = 4.8 × 10^-10 esu]

Which of the following is correct about a plant which has a good level of abscisic acid?

Which of the following structures give rise to the female gametophyte in angiosperms?

Which of the following characteristics of fungi differentiates them from algae?

The middle lamella of a cell wall is rich in

Which of the following membranes has the highest amount of proteins?

If one cell cycle takes 100 minutes for completion, then time spent in M-phase is

Pachytene phase of meiosis is characterised by which of the following?

Match the following columns and select the correct option.

Which of the following represents the correct sequence of flow of electrons in light reaction of photosynthesis?

The curling of Rhododendron leaves is an example of

Which of the following effects of auxins on plants is the basis for commercial application?

Who gave the term ‘Nuclein’ to the acidic substance present in nucleus?

Number of base pairs in the DNA of Escherichia coli is

A linear dsDNA has 1.8 × 10⁴ phosphodiester bonds. Number of bases in this DNA will be

Pyrimidines present in both RNA and DNA is/are

In the field of molecular genetics, what was the contribution of Watson and Crick?

Which of the following is 9-membered double-ring structure?

Regarding reverse central dogma of molecular biology that occurs in some viruses, the flow of information is from

Histones are

The regions in chromatin which are lightly stained

Which of the following strains of Pneumococcus when injected to mice will cause death of that mice?

Through the experiments conducted by A. Hershey and M. Chase, it was provided that

In the experiment conducted by Hershey and Chase, the supernatant has

In the following question, the Assertions (A) and Reason (R) have been put forward. Read both the statements and choose the correct option from the following.

Assertion: Sunflower and Rose are bisexual flowers.

Reason: Flowers in which, the thalamus grows around the ovary fusing with its wall are called epigynous flowers.

Given below are two statements:

Statement I: The primary CO₂ acceptor in C₄ plants is phosphoenolpyruvate and is found in the mesophyll cells

Statement II: Mesophyll cells in C₄ plants lack RuBisCo enzyme.

In the light of the above statements, choose the correct answer from the options given below:

Which of the following criteria should not be true for the molecules that act as genetic material?

Which of the following statements is correct with respect to taxonomic aids?

Binomial nomenclature means:

Who proposed binomial nomenclature?

The sequence of characteristics of a taxonomical study is:

Which taxonomic category is the poales of wheat?

According to the binomial nomenclature system, the snow leopard's full name is

The biological concept of species is mainly based on

The study of taxonomy begins with:

'Systematics' refers to the

Ti plasmid is often used for making transgenic plants. This plasmid is found in

RNA is a single strand or chain which is formed by end to end polymerisation of a number of ribonucleotides or ribotides. Which of the following RNAs is an adapter molecule which is meant for transferring amino acids to ribosomes for synthesis of polypeptides?

While considering the grassland ecosystem for pyramid of numbers, match the different trophic level components with the number of individuals and select the correct option.

Which of the following are examples of water-pollinated plants?

A. Vallisneria

B. Hydrilla

C. Water hyacinth

D. Water lily

Which of the following is expected when a test tube of sterile water containing a typical animal cell and a typical plant cell is incubated at 37oC for 24 hours?

In the following question, the Assertions (A) and Reason (R) have been put forward. Read both the statements and choose the correct option from the following.

Assertion: Pea has vexillary type of aestivation.

Reason: In this type of aestivation, the posterior petal is the largest and covers almost the two lateral petals, and the latter in their turn, nearly overlap the two anterior or smallest petals.

Which one of the following statements for pyramid of energy is incorrect, whereas the remaining three are correct?

The nitrogenous bases in DNA are

Protein synthesis in an animal cell occurs

Which of the following is the highest in the hierarchy of taxonomic category?

Where are the genital openings of an earthworm present?

Hürthle cell is associated with

What is Test Tube Baby?

Which of the following events is affected by the presence and distribution of yolk in the egg?

Which of these disorders is the odd one?

The genetic constitution of 44 autosomes and XO sex chromosomes in a human female indicates

RNA retroviruses have a special enzyme that

What type of freely movable joint is present in between atlas and axis?

Carcinoma refers to

The genetic defect of adenosine deaminase (ADA) deficiency may be cured permanently by

Proinsulin contains

Which of the following interferes with the transport of the neuro-transmitter dopamine and its excess dosage can cause hallucinations?

Read the following statements and choose the correct option

A. Agrobacterium tumefaciens, a pathogen of several dicot plants, is able to deliver a piece of DNA known as ‘T-DNA’ into plant host cells, transforming them.

B. Non disarmed retroviruses are used to deliver desirable genes into animal cells.

Which of the following options shows the correct combination of aquatic mammals?

Which of the following has an organ level of structural organisation?

Which of the following animals has bilateral symmetry?

In sea anemone, the symmetry is

In which of the following groups does a larval stage occur in the life history of all members of the group?

Male cockroach can be identified from the female by the presence of

Where do you find hepatic caecae in Periplaneta americana?

What external changes are visible after the last moult of a cockroach nymph?

The terga, sterna and pleura of cockroach body are joined by

Which of the following features is not present in Periplaneta americana?

In male cockroaches, sperms are stored in which part of the reproductive system?

Which of the following is not a part of reproductive system of female cockroach?

Blood corpuscles are formed in the:

Stratified epithelium is found in

Which of these statements is true about the respiratory system of cockroach?

Ootheca is a dark reddish to blackish brown capsule which stores:

Which of the following layers forms the diffusion membrane in the alveoli?

__________ is situated adjacent to the rhythm centre which is highly sensitive to CO₂ and hydrogen ions.

A centre present in the ________ of the brain called pneumotaxic centre can moderate the functions of the respiratory rhythm centre.

Which of the following statements is correct about the alveoli of the lungs?

Select the option which gives the correct function and/or characteristic of the part of the human respiratory system.

In sponges, the exchange of gases occurs through:

Which of the following is not a correct match?

Which one of the following conditions correctly describes the manner of determining the sex in the given example?

Which one of the following aspects is not a component of functional unit of ecosystem?

Adenosine, guanosine, thymidine, uridine, cytidine are all _______ but adenylic acid, guanylic acid, uridylic acid, cytidylic acid are ________.

In the following question, the Assertions (A) and Reason (R) have been put forward. Read both the statements and choose the correct option from the following.

Assertion: Nucleic acids exhibit secondary structure.

Reason: It is the linear sequence of amino acids in a polypeptide chain.

Oviducts are lined by

Which of the following areas in India is a hotspot of biodiversity?

Select the correct sequence of steps in DNA finger printing involving southern blot hybridisation using VNTR.

i. Hybridisation using labelled VNTR probe

ii. Isolation of DNA

iii. Transferring (blotting) of DNA fragments to synthetic membranes, such as nitrocellulose or nylon

iv. Detection of hybridised DNA fragments by autoradiograph

v. Separation of DNA fragments by electrophoresis

vi. Digestion of DNA by restriction endonucleases

Which of the following is the most frequently used techniques in DNA fingerprinting?

Which of the following structures is/are found to be damaged in emphysema?