Gold dissolves in cyanide solution the presence of air to form [Au(CN)_(3)] which is stable in a cons solution. Au_((s))+CN_((s))^(-)+O_(2)+H_(2)O_(2) hArr [Au(CN)_(2)]_((aq))^(-)+OH_((aq))^(-) Aquaregia a 3 : 1 mixture of conc. HC and HNO_(3) was developed by the alchemists as a means to dissolve gold. The process is actually a Redox reaction. Au_((s))+NO_(3(aq))+Cl^(-) hArr AuCl_(4(aq))^(-)+NO_(2(g)) Gold is too noble to react with HNO_(3) However gold does react with a waregia becuase the complex AuCl_(4)^(-) forms Au_((aq))^(+3)+3e^(-) to Au_((s)) E^(theta)=15V to I AuCl_(4(aq))^(-)+3e^(-) to Au_((s))+4Cl_((q))^(-)E^(0)=1V to 2 How many grams, approximately of NACN are needed to extract 20g of gold from are?

Gold dissolves in cyanide solution the presence of air to form [Au(CN)

1.	Gold dissolves in cyanide solution the presence of air to form [Au(CN)_(3)] which is stable in a cons solution. Au_((s))+CN_((s))^(-)+O_(2)+H_(2)O_(2) hArr [Au(CN)_(2)]_((aq))^(-)+OH_((aq))^(-) Aquaregia a 3 : 1 mixture of conc. HC and HNO_(3) was developed by the alchemists as a means to dissolve gold. The process is actually a Redox reaction. Au_((s))+NO_(3(aq))+Cl^(-) hArr AuCl_(4(aq))^(-)+NO_(2(g)) Gold is too noble to react with HNO_(3) However gold does react with a waregia becuase the complex AuCl_(4)^(-) forms Au_((aq))^(+3)+3e^(-) to Au_((s)) E^(theta)=15V to I AuCl_(4(aq))^(-)+3e^(-) to Au_((s))+4Cl_((q))^(-)E^(0)=1V to 2 How many grams, approximately of NACN are needed to extract 20g of gold from are?
Answer» 20 g `6.5 g` `10 g` `8 g` Solution :`Au_(2)S+4NaCN hArr underset((x))(2Na[AU(CN)_(2)])+Na_(2)S` `2Na[Au(CN)_(2)]^(-)+ZN to Na_(2)[Zn(CN)_(4)]+2Au` `196......2xx197` `x......20` `169xx20=x xx 2xx197` `:.x=(196xx20)/(2xx197)=10 gm`