Which of the following base is NOT present in DNA?

Which one of the following salts would have the same value of the van't Hoff factor as that of \(\text{Al(NO}_3\text{)}_3\)?

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The carbonyl group of aldehydes and ketones is highly polar. The positively charged carbon is readily attacked by electron-rich nucleophile and the negatively charged oxygen atom is attacked by an electro-deficient electrophile. Aldehydes and ketones undergo nucleophilic addition reactions in the presence of acid or a base. The mechanism involves attack of a nucleophile on the electron deficient carbonyl carbon to form a tetrahedral intermediate. A new bond is formed between the carbon and oxygen. Protonation of the anion furnished by the reaction medium yields a neutral addition product. The addition product is same whether the reaction is catalyzed by acid or a base. For example in the presence of base aldehydes and ketones react with hydrogen cyanide to form cyanohydrin.
The source of nucleophile in the base catalyzed cyanohydrin formation is:

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Carbohydrates such as cane sugar, glucose, starch etc. belong to a class of naturally occurring organic compounds. Structurally these are polyhydroxy aldehydes or ketones or the compounds which produce such units on hydrolysis. Carbohydrates which are sweet in taste are called sugars. Theses sugars can be reducing or non-reducing. Monosaccharides cannot be hydrolyzed to simpler units whereas Oligosaccharides yield two to ten monosaccharide units on hydrolysis. Polysaccharides yield large number of monosaccharide units on hydrolysis. This class of biomolecules is essential for living systems as they serve as storage molecules in plants and animals. In addition, they provide raw materials for important industries like furniture, textiles, paper, lacquers and breweries. Two aldopentose form important constituents of nucleic acids. Carbohydrates are also called saccharides (Greek: sakcharon which means sugar). Sugar which is used in household and in milk also comes under this class of biomolecules.
Reducing sugars respond to

Arrange the following compounds in increasing order of their \(\text{pKa}\) values.
(A) o-nitrophenol
(B) m-nitrophenol
(C) Phenol
(D) Ethanol
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Identify the correct order of organic compounds in the following chemical reaction: ? + Mg → ? → ? → ?
(A) CH 3 MgBr
(B) CH 3 B
(B) CH 3 B
(D) CH 4
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Match the properties given in List-I with the metals given in List-II

List-I (Property)	List-II (Metal)
(A) 3d series element with highest melting point	(I) Os
(B) element which can show +8 oxidation state	(II) Fe
(C) 3d series element with largest number of oxidation states	(III) Cr
(D) constituent of Mischmetall	(IV) Mn

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The fringe width in Young's double slit experiment is \( 2.4 \times 10^{-4} \, \text{m} \), when red light of wavelength 6400 \( \text{\AA} \) is used. The decrease in the fringe width, if light of wavelength 4000 \( \text{\AA} \) is used instead of red light, will be:

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Adsorption is the phenomenon of attracting and retaining the molecules of a substance on the surface of a solid resulting into a higher concentration on the surface than in the bulk. The substance adsorbed is known as adsorbate and the substance on which adsorption takes place is called adsorbent. In physisorption adsorbate is held to the adsorbent by weak van der Waals forces and in chemisorption by strong chemical bond.
In coagulation of a positive sol, the flocculating power will be in the order:
A. \(PO _4^{3-}\)
B. \(Cl ^{-}\)
C. \([ Fe ( CN )]^{3-}\)
D. \(SO _4^{2-}\)
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What does a negative \(E ^{\circ}\) (standard reduction potential) value of a redox couple indicate?

Which of the following statement(s) is are NOT corect about codon AUG
A. It acts an initiator Cadon.
B. It acts as a release factor
C. It has dual function.
D. It code for methionine
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What is the approximate earth's dipole moment, if the earth's magnetic field at the Equator is approximately 0.5 G and diameter is \( 15.0 \times 10^6 \text{ m} \)?

In class XII, suppose \(5 \% \) of boys and \(0.25\%\) of girls are physically fit for a game.
A fit student is selected at random from this class having same number of boys and girls.
If the probability that the selected student is a girl is \(\frac{m}{n}\), \(\operatorname{gcd}(m, n)=1\), then \(m+n\) is equal to