Why are cimetidine and ranitidine better antacids than sodium hydrogencarbonate or magnesium or aluminium hydroxide ?
Antacids such as sodium hydrogen carbonate, magnesium hydroxide, and aluminium hydroxide work by neutralizing the excess hydrochloric acid present in the stomach. However, the root cause for the release of excess acid remains untreated.
Cimetidine and rantidine are better antacids as they control the root cause of acidity. These drugs prevent the interaction of histamine with the receptors present in the stomach walls. Consequently, there is a decrease in the amount of acid released by the stomach. This is why cimetidine and rantidine are better antacids than sodium hydrogen carbonate, magnesium hydroxide, and aluminium hydroxide.
Why do soaps not work in hard water?
Explain the following terms with suitable examples
(i) cationic detergents
(ii) anionic detergents and
(iii) non-ionic detergents.
What are food preservatives ?
Sleeping pills are recommended by doctors to the patients suffering from sleeplessness but it is not advisable to take its doses without consultation with the doctor, Why?
How do antiseptics differ from disinfectants ? Give one example of each.
Why is use of aspartame limited to cold foods and drinks?
What are the main constituents of dettol?
With reference to which classification has the statement, ranitidine is an antacid been given?
Write the chemical equation for preparing sodium soap from glyceryl oleate and glyceryl palmitate. Structural formulae of these compounds are given below.
(i) (C15H31COO)3 C3H5 - Glyceryl palmitate
(ii)(C17H33COO)3 C3H5 - Glyceryl oleate
Name a substance which can be used as an antiseptic as well as disinfectant.
For the reaction R → P, the concentration of a reactant changes from 0.03 M to 0.02 M in 25 minutes. Calculate the average rate of reaction using units of time both in minutes and seconds.
Write the formulas for the following coordination compounds:
(i) Tetraamminediaquacobalt (III) chloride
(ii) Potassium tetracyanonickelate(II)
(iii) Tris(ethane-1,2-diamine) chromium(III) chloride
(iv) Amminebromidochloridonitrito-N-platinate(II)
(v) Dichloridobis(ethane-1,2-diamine)platinum(IV) nitrate
(vi) Iron(III) hexacyanoferrate(II)
(i) Write structures of different isomeric amines corresponding to the molecular formula, C4H11N
(ii) Write IUPAC names of all the isomers.
(iii) What type of isomerism is exhibited by different pairs of amines?
Why are solids rigid?
Write any two characteristics of Chemisorption.
Write the structures of the following compounds.
(i) α-Methoxypropionaldehyde
(ii) 3-Hydroxybutanal
(iii) 2-Hydroxycyclopentane carbaldehyde
(iv) 4-Oxopentanal
(v) Di-sec-butyl ketone
(vi) 4-Fluoroacetophenone
Which of the ores mentioned in Table 6.1 can be concentrated by magnetic separation method?
Why are pentahalides more covalent than trihalides?
Silver atom has completely filled d orbitals (4d10) in its ground state. How can you say that it is a transition element?
Glucose or sucrose are soluble in water but cyclohexane or benzene (simple six membered ring compounds) are insoluble in water. Explain.
Why has it been difficult to study the chemistry of radon?
The rate constant for the first order decomposition of H2O2 is given by the following equation:
log k = 14.34 - 1.25 x 104 K/T
Calculate Ea for this reaction and at what temperature will its half-period be 256 minutes?
Ortho and para nitrophenols are more acidic than phenol. Draw the resonance structures of the corresponding phenoxide ions.
Compare the chemistry of actinoids with that of the lanthanoids with specialreference to:
(i) electronic configuration
(ii) atomic and ionic sizes
(iii) oxidation stateand
(iv) chemical reactivity.
How will you convert?
(i) Benzene into aniline
(ii) Benzene into N, N-dimethylaniline
(iii) Cl-(CH2)4-Cl into hexan-1, 6-diamine?
An organic compound with the molecular formula C9H10O forms 2, 4-DNP derivative, reduces Tollens' reagent and undergoes Cannizzaro reaction. On vigorous oxidation, it gives 1, 2-benzenedicarboxylic acid. Identify the compound.
Arrange the following compounds in increasing order of their reactivity in nucleophilic addition reactions.
(i)Ethanal, Propanal, Propanone, Butanone.
(ii)Benzaldehyde, p-Tolualdehyde, p-Nitrobenzaldehyde, Acetophenone.
Hint:Consider steric effect and electronic effect.
What is the role of desorption in the process of catalysis?
Out of C6H5CH2Cl and C6H5CHClC6H5, which is more easily hydrolysed by aqueous KOH?
What is meant by the following terms? Give an example of the reaction in each case.
(i) Cyanohydrin (ii) Acetal
(iii) Semicarbazone
(iv) Aldol
(v) Hemiacetal
(vi) Oxime
(vii) Ketal
(vii) Imine
(ix) 2,4-DNP-derivative
(x) Schiff's base
Ncert question number 16.11 exercise Answers very useful
Useful in emergency
Really helpful
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