9 public questions tagged with this topic.
CH₂OH-CHOH-CH₂OH is a trihydric alcohol with three -OH groups on a 3-carbon chain, commonly known as glycerol.
Ref: NCERT Class 12 Chemistry > Chapter 7: Alcohols, Phenols and Ethers > Topic: Preparation of Alcohols - from Alkenes Haloalkanes Carbonyls Grignard
A trihydric alcohol has three -OH groups. Glycerol (CH₂OH-CHOH-CH₂OH) is a trihydric alcohol, also known as propane-1,2,3-triol.
Ref: NCERT Class 12 Chemistry > Chapter 7: Alcohols, Phenols and Ethers > Topic: Preparation of Alcohols - from Alkenes Haloalkanes Carbonyls Grignard
CH₃-CH(OH)-CH₂-OH (propane-1,2-diol) is a 3-carbon diol, commonly known as propylene glycol.
Ref: NCERT Class 12 Chemistry > Chapter 7: Alcohols, Phenols and Ethers > Topic: Preparation of Alcohols - from Alkenes Haloalkanes Carbonyls Grignard
Propane-1,2,3-triol (glycerol, CH₂OH-CHOH-CH₂OH) has three -OH groups, as indicated by ‘triol’ in its name.
Ref: NCERT Class 12 Chemistry > Chapter 7: Alcohols, Phenols and Ethers > Topic: Physical Properties and Acidity of Alcohols and Phenols
Glycerol (CH₂OH-CHOH-CH₂OH) has three -OH groups, forming extensive hydrogen bonding, which increases its boiling point compared to ethanol with one -OH group.
Ref: NCERT Class 12 Chemistry > Chapter 7: Alcohols, Phenols and Ethers > Topic: Classification and Nomenclature and Structures of Alcohols Phenols Ethers
Glycerol (HO-CH₂-CH(OH)-CH₂-OH) has a 3-carbon chain with -OH groups on all three carbons, named propane-1,2,3-triol in IUPAC nomenclature.
Ref: NCERT Class 12 Chemistry > Chapter 7: Alcohols, Phenols and Ethers > Topic: Classification and Nomenclature and Structures of Alcohols Phenols Ethers
Moles of glycerol = (10/92) ≈ 0.1087 mol . Mass of solvent = 200 g = 0.2 kg. Molality = (0.1087/0.2) ≈ 0.5435 mol/kg .
Ref: NCERT Class 12 Chemistry > Chapter 1: Solutions > Topic: Abnormal Molar Masses and van't Hoff Factor
Loading dyes require a dense component to ensure samples settle at the bottom of wells immersed in running buffer. Glycerol at 5 to 10 percent (v/v) increases specific gravity and viscosity without adding charge, so it does not alter electric field migration. It is chemically inert, transparent, and inexpensive. Sucrose and Ficoll perform similar functions as alternatives. Glycerol does not stain DNA, nor affect conductivity or voltage significantly; its role is strictly physical, preventing sample dispersal and ensuring sharp, well-defined entry into the gel matrix during loading.
Ref: NCERT Biology Class XII Principles on Klenow fill-in labeling, Lehninger Chapter 9 DNA cloning techniques, and Molecular Cloning by Sambrook Chapter 10 documenting end-labeling of cohesive termini.
DNA samples must sink into wells despite buffer overlay. Loading buffers contain high-density solutes such as sucrose, glycerol, or Ficoll to increase sample specific gravity above that of the running buffer, preventing diffusion. Sucrose at 10 to 40 percent is commonly used because it is uncharged, chemically inert, and does not interfere with migration. Ethidium bromide is an intercalating fluorophore for visualization. Bromophenol blue is an anionic tracking dye marking front migration. TEMED catalyzes polyacrylamide polymerization. Thus, sucrose functions purely as a densifying agent for well loading.
Ref: NCERT Biology Class XII Principles on Klenow fill-in labeling, Lehninger Chapter 9 DNA cloning techniques, and Molecular Cloning by Sambrook Chapter 10 documenting end-labeling of cohesive termini.
