. high temperature to 'y at low temperature. w is it related to the 15 not of the vhich contract on heating. owing Ans. Water from 0°C to 4°C, at the silver iodide from 80°C to 141°C. 10. What do you mean by anomalous expansion of water? lan Ans. Expansion of water on cooling it from 4°C to0°C. 11. At what temperature the density of water is maximum ? State its value. Ans. At 4°C, 1000 kg m-3 h we I = 0.24 cal (nearly) S.I. unit. ouched with hand, C th heat passes from r hand to the ice. rature. expansion of a 12. State the volume changes observed when a given mass of water is heated from 0°C to 10ºC. Sketch a temperature-volume graph to show the behaviour. 13. Draw a graph to show the variation in density of water with temperature in the temperature range from 0°C to 10°C. 14. A given mace of
Answers
Answer:
Gallium is found primarily in the +3 oxidation state. The +1 oxidation state is also found in some compounds, although it is less common than it is for gallium's heavier congeners indium and thallium. For example, the very stable GaCl2 contains both gallium(I) and gallium(III) and can be formulated as GaIGaIIICl4; in contrast, the monochloride is unstable above 0 °C, disproportionating into elemental gallium and gallium(III) chloride. Compounds containing Ga–Ga bonds are true gallium(II) compounds, such as GaS (which can be formulated as Ga24+(S2−)2) and the dioxan complex Ga2Cl4(C4H8O2)2.[27]
Aqueous chemistry Edit
Strong acids dissolve gallium, forming gallium(III) salts such as Ga(NO
3)
3 (gallium nitrate). Aqueous solutions of gallium(III) salts contain the hydrated gallium ion, [Ga(H
2O)
6]3+
.[28]: 1033 Gallium(III) hydroxide, Ga(OH)
3, may be precipitated from gallium(III) solutions by adding ammonia. Dehydrating Ga(OH)
3 at 100 °C produces gallium oxide hydroxide, GaO(OH).[29]: 140–141
Alkaline hydroxide solutions dissolve gallium, forming gallate salts (not to be confused with identically named gallic acid salts) containing the Ga(OH)−
4 anion.[30][28]: 1033 [31] Gallium hydroxide, which is amphoteric, also dissolves in alkali to form gallate salts.[29]: 141 Although earlier work suggested Ga(OH)3−
6 as another possible gallate anion,[32] it was not found in later work.[31]
Oxides and chalcogenides Edit
Gallium reacts with the chalcogens only at relatively high temperatures. At room temperature, gallium metal is not reactive with air and water because it forms a passive, protective oxide layer. At higher temperatures, however, it reacts with atmospheric oxygen to form gallium(III) oxide, Ga
2O
3.[30] Reducing Ga
2O
3 with elemental gallium in vacuum at 500 °C to 700 °C yields the dark brown gallium(I) oxide, Ga
2O.[29]: 285 Ga
2O is a very strong reducing agent, capable of reducing H
2SO
4 to H
2S.[29]: 207 It disproportionates at 800 °C back to gallium and Ga
2O
3.[33]
Gallium(III) sulfide, Ga
2S
3, has 3 possible crystal modifications.[33]: 104 It can be made by the reaction of gallium with hydrogen sulfide (H
2S) at 950 °C.[29]: 162 Alternatively, Ga(OH)
3 can be used at 747 °C:[34]
2 Ga(OH)
3 + 3 H
2S → Ga
2S
3 + 6 H
2O
Reacting a mixture of alkali metal carbonates and Ga
2O
3 with H
2S leads to the formation of thiogallates containing the [Ga
2S
4]2−
anion. Strong acids decompose these salts, releasing H
2S in the process.[33]: 104–105 The mercury salt, HgGa
2S
4, can be used as a phosphor.[35]
Gallium also forms sulfides in lower oxidation states, such as gallium(II) sulfide and the green gallium(I) sulfide, the latter of which is produced from the former by heating to 1000 °C under a stream of nitrogen.[33]: 94
The other binary chalcogenides, Ga
2Se
3 and Ga
2Te
3, have the zincblende structure. They are all semiconductors but are easily hydrolysed and have limited utility.[33]: 104
Answer:
. high temperature to 'y at low temperature. w is it related to the 15 not of the vhich contract on heating. owing Ans. Water from 0°C to 4°C, at the silver iodide from 80°C to 141°C. 10. What do you mean by anomalous expansion of water? lan Ans. Expansion of water on cooling it from 4°C to0°C. 11. At what temperature the density of water is maximum ? State its value. Ans. At 4°C, 1000 kg m-3 h we I = 0.24 cal (nearly) S.I. unit. ouched with hand, C th heat passes from r hand to the ice. rature. expansion of a 12. State the volume changes observed when a given mass of water is heated from 0°C to 10ºC. Sketch a temperature-volume graph to show the behaviour. 13. Draw a graph to show the variation in density of water with temperature in the temperature range from 0°C to 10°C. 14. A given mace of
HEY BUDDY
MUGHE KUCH V NHI HUA HAI!!
SO
DON'T WORRY!!
YRR I DON'T KNOW BSS MOOD KIYA TOH LAGA LIYA!!
YRR I WANT TO LEAVE THIS PLATFORM !!
BUT I AM NOT ABLE TO LEAVE IT!!
THANKS FOR YOUR CONCERN !!
BUT I AM GOING TO LEAVE THIS APP FOREVER!!
I DON'T WANT TO TALK TO __________!!
__________ IS A LIER!!!
THANK YOU!!