Answer
Verified
357.3k+ views
Hint: Silver halides ($AgX$ ) are ionic crystals consisting of a regular cubic lattice of $Ag$ and halide ions together with a small proportion of defects, such as $Ag$ ions that have been displaced from their regular lattice position to another “interstitial” position (the Ag ions are much smaller than the halide ions), and the corresponding vacancy in the lattice.
Complete step by step answer:
Silver halides are used in photography because they are photosensitive as they react with light to form the image, silver halides being reduced to silver.
Hence the correct option is (A).
In $AgX$, all the energy levels of the highest occupied energy band (the valence band, VB) are filled with electrons. Although the electrons are delocalized, any increase of one electron's momentum under the action of an electric field must be balanced by a reduction of momentum of another one, because spare energy states are available. Thus, in a perfect crystal, essentially no electronic conduction occurs. The next higher energy band (the conduction band, CB) is essentially empty in a perfect $AgX$ crystal, being too far (2.5 eV or so) above the VB for significant thermally excited transitions to take place from the VB. In a perfect crystal, there are no energy levels in the gap between the VB and CB, but in real microcrystals there are a few such levels associated with crystal defects. These defect states are critical to photosensitivity. It has been shown experimentally that the purest, most perfect crystals of $AgX$ are virtually insensitive to light.
Note:
Silver halides, except for silver fluoride, are very insoluble in water. Silver nitrate can be used to precipitate halides; this application is useful in quantitative analysis of halides. The three main silver halide compounds have distinctive colors that can be used to quickly identify halide ions in a solution. The silver chloride compound forms a white precipitate, silver bromide a creamy colored precipitate and silver iodide a yellow colored precipitate. They are also soluble in hypo solution.
Complete step by step answer:
Silver halides are used in photography because they are photosensitive as they react with light to form the image, silver halides being reduced to silver.
Hence the correct option is (A).
In $AgX$, all the energy levels of the highest occupied energy band (the valence band, VB) are filled with electrons. Although the electrons are delocalized, any increase of one electron's momentum under the action of an electric field must be balanced by a reduction of momentum of another one, because spare energy states are available. Thus, in a perfect crystal, essentially no electronic conduction occurs. The next higher energy band (the conduction band, CB) is essentially empty in a perfect $AgX$ crystal, being too far (2.5 eV or so) above the VB for significant thermally excited transitions to take place from the VB. In a perfect crystal, there are no energy levels in the gap between the VB and CB, but in real microcrystals there are a few such levels associated with crystal defects. These defect states are critical to photosensitivity. It has been shown experimentally that the purest, most perfect crystals of $AgX$ are virtually insensitive to light.
Note:
Silver halides, except for silver fluoride, are very insoluble in water. Silver nitrate can be used to precipitate halides; this application is useful in quantitative analysis of halides. The three main silver halide compounds have distinctive colors that can be used to quickly identify halide ions in a solution. The silver chloride compound forms a white precipitate, silver bromide a creamy colored precipitate and silver iodide a yellow colored precipitate. They are also soluble in hypo solution.
Recently Updated Pages
Basicity of sulphurous acid and sulphuric acid are
Three beakers labelled as A B and C each containing 25 mL of water were taken A small amount of NaOH anhydrous CuSO4 and NaCl were added to the beakers A B and C respectively It was observed that there was an increase in the temperature of the solutions contained in beakers A and B whereas in case of beaker C the temperature of the solution falls Which one of the following statements isarecorrect i In beakers A and B exothermic process has occurred ii In beakers A and B endothermic process has occurred iii In beaker C exothermic process has occurred iv In beaker C endothermic process has occurred
What is the stopping potential when the metal with class 12 physics JEE_Main
The momentum of a photon is 2 times 10 16gm cmsec Its class 12 physics JEE_Main
How do you arrange NH4 + BF3 H2O C2H2 in increasing class 11 chemistry CBSE
Is H mCT and q mCT the same thing If so which is more class 11 chemistry CBSE